Browsing by Author "Zeng, R"
Now showing 1 - 20 of 35
Results Per Page
Sort Options
- ItemCritical magnetic transition in TbNi2Mn-magnetization and Mössbauer spectroscopy(IOP Publishing LTD, 2011-06-01) Wang, JL; Campbell, SJ; Kennedy, SJ; Zeng, R; Dou, SX; Wu, GHThe structural and magnetic properties of the TbNi2Mnx series (0.9 ≤ x ≤ 1.10) have been investigated using x-ray diffraction, field- and temperature-dependent AC magnetic susceptibility, DC magnetization (5–340 K; 0–5 T) and 57Fe Mössbauer spectroscopy (5–300 K). TbNi2Mnx crystallizes in the MgCu2-type structure (space group Fd\bar {3}m ). The additional contributions to the magnetic energy terms from transition-metal–transition-metal interactions (T–T) and rare-earth–transition-metal interactions (R–T) in RNi2Mn compounds contribute to their increased magnetic ordering temperatures compared with RNi2 and RMn2. Both the lattice constant a and the Curie temperature TC exhibit maximal values at the x = 1 composition indicating strong magnetostructural coupling. Analyses of the AC magnetic susceptibility and DC magnetization data of TbNi2Mn around the Curie temperature TC = 147 K confirm that the magnetic transition is second order with critical exponents β = 0.77 ± 0.12, γ = 1.09 ± 0.07 and δ = 2.51 ± 0.06. These exponents establish that the magnetic interactions in TbNi2Mn are long range despite mixed occupancies of Tb and Mn atoms at the 8a site and vacancies. The magnetic entropy − ΔSM around TC is proportional to (μ0H/TC)2/3 in agreement with the critical magnetic analyses. The Mössbauer spectra above TC are fitted by two sub-spectra in agreement with refinement of the x-ray data while below TC three sub-spectra are required to represent the three inequivalent local magnetic environments.(c) 2011 IOP Publishing LTD
- ItemDevelopment of advanced diluted magnetic semiconductors with rare earth doping technology(University of Western Australia, 2007-10-15) Photongkam, P; Ionescu, M; Zeng, R; Yu, DH; Li, S
- ItemEffects of Cr substitution on structural and magnetic properties in La0.7Pr0.3Fe11.4Si1.6 compound(AIP Scitation, 2014-04-03) Din, MFM; Wang, JL; Studer, AJ; Gu, QF; Zeng, R; Debnath, JC; Shamba, P; Kennedy, SJ; Dou, SXIn an effort to explore the effect of substitution Fe by Cr in NaZn13-type La0.7Pr0.3Fe11.4−xCrxSi1.6 (x = 0, 0.06, 0.12, 0.26, and 0.34) compounds, the structure and magnetic properties have been investigated by high intensity of x-ray and neutron diffraction, scanning electron microscopy, specific heat, and magnetization measurement. It has been found that a substitution of Cr for Fe in this compounds leads to decrease in the lattice parameter a at room temperature but variation on Curie temperature (TC). While the first order nature of magnetic phase transition around TC does not change with increasing Cr content up to x = 0.34. High intensity x-ray and neutron diffraction study at variable temperatures for highest Cr concentration x = 0.34 confirmed the presence of strong magneto-volume effect around TC and indicated the direct evident of coexistence across magnetic transition as characteristic of first order nature. The values of −ΔSM around TC decrease from 17 J kg−1 K−1 for x = 0 to 12 J kg−1 K−1 for x = 0.06 and then increases with further increasing Cr content up to 17.5 J kg−1 K−1 for x = 0.34 under a change of 0–5 T magnetic field. Similar behavior on relative cooling power which is decrease from 390 J kg−1 for x = 0 to 365 J kg−1 for x = 0.06 at the beginning and then increases up to 400 J kg−1 for x = 0.34. From the point of this view with the highest Cr concentration (x = 0.34) exhibits favourable material candidate for magnetic refrigerator application therefore should inspire further study concerning on higher Cr concentration in this compound. © 2014, AIP Publishing LLC.
- ItemEffects of Cu substitution on structural and magnetic properties of La0.7Pr0.3Fe11.4Si1.6 compounds(Elsevier Ltd., 2013-05-01) Din, MFM; Wang, JL; Zeng, R; Shamba, P; Debnath, JC; Dou, SXThe structure and magnetic properties of the La0.7Pr0.3Fe11.4−xCuxSi1.6 compounds have been investigated by X-ray diffraction, scanning electron microscopy and magnetisation measurements. Cu substitution for Fe in La0.7Pr0.3Fe11.4−xCuxSi1.6 (x = 0, 0.06, 0.12, 0.23, 0.34) leads to a reduction in hysteresis loss, a decrease in magnetic entropy change but an increase in Curie temperature (TC). The influences of annealing processes at different temperatures on TC, magnetic hysteresis, and the magnetocaloric effect (MCE) of La0.7Pr0.3Fe11.4Si1.6 are investigated in detail. It has been found that a short-time and high temperature annealing process has benefits for the formation of the NaZn13 types as phase compared to a long-time and low temperature annealing process. © 2013, Elsevier Ltd.
- ItemEnhancement of the refrigerant capacity in low level boron doped La0.8Gd0.2Fe11.4Si1.6(Elsevier Science BV., 2013-06-01) Shamba, P; Zeng, R; Wang, JL; Campbell, SJ; Dou, SXThe effects of boron doping on the itinerant-electron metamagnetic (IEM) transition and the magnetocaloric effects (MCEs) in the cubic NaZn13-type La0.8Gd0.2Fe11.4Si1.6 compound have been investigated. The Curie temperature, TC, of La0.8Gd0.2Fe11.4Si1.6Bx compounds with x=0, 0.03, 0.06, 0.2 and 0.3 was found to increase from 200 K to 222 K with increase in boron doping, x. The maximum values of the isothermal magnetic entropy change, Delta S-M, (derived using the Maxwell relation for a field change ΔB=0–5 T) in La0.8Gd0.2Fe11.4Si1.6Bx with x=0, 0.03, 0.06, 0.2 and 0.3 are 14.8, 16, 15, 7.5 and 6.6 J kg−1 K−1 respectively, with corresponding values of the refrigerant capacity, RCP of 285, 361, 346, 222 and 245 J kg−1. The large Delta S-M values observed for the undoped sample, and the low level B doped La0.8Gd0.2Fe11.4Si1.6B0.03 and La0.8Gd0.2Fe11.4Si1.6B0.06 compounds are attributed to the first order nature of the IEM transition while the decrease of Delta S-M at x=0.2 and 0.3 is due to a change in the second order phase transition with increase in B doping. The nature of the magnetic phase transitions is also reflected by the magnetic hysteresis of 3.7, 9, 5.7, 0.4 and 0.3 J kg−1 for x=0.0, 0.03, 0.06, 0.2 and 0.30 respectively. The possibility of tuning the TC and the magnetocaloric properties at temperatures close to room temperature make this system interesting from the points of view of both fundamental aspects as well as applications. © 2013, Elsevier Ltd.
- ItemLarge magnetocaloric effect in re-entrant ferromagnet PrMn1.4Fe0.6Ge2(Elsevier, 2011-02-17) Zeng, R; Dou, SX; Wang, JL; Campbell, SJMagnetocaloric effects (MCE) at multiple magnetic phase transition temperatures in PrMn1.4Fe0.6Ge2 were investigated by heat capacity and magnetization measurements. PrMn1.4Fe0.6Ge2 is of a re-entrant ferromagnet and performs multiple magnetic phase transitions in the temperature range from 5 to 340 K. A large magnetic entropy change (−ΔSM) 8.2 J/kg K and adiabatic temperature change (ΔTad) 4.8 K are observed for a field change of 0–1.5 T around 25.5 K, associated with the field-induced first order magnetic phase transition (FOMT) from the antiferromagnetic to the ferromagnetic state with an additional Pr magnetic contribution. These results suggest that a re-entrant ferromagnet is probably promising candidate as working material in the hydrogen and nature gas liquefaction temperature range magnetic refrigeration technology. © 2010, Elsevier Ltd.
- ItemMagnetic and structural properties of intermetallic NdMn2-xTixSi2 compounds(Australian Optical Society, 2012-01-01) Din, MFM; Wang, JL; Zeng, R; Shamba, P; Hutchison, WD; Avdeev, M; Kennedy, SJ; Campbell, SJGiant magnetocalorie effects have been observed in NdMn2-xTixSi2 around the Curie Temperature Tc (with AB = 5-0 T.) The magnetic entropy charge decreases with increasing x from 27 J kg- K- for x=0 to 10 J kg- K- for x =0.3. Neutron investigations indicate that magnetostructural coupling contribution plays a critical role in the large value of magnetic entropy change.
- ItemMagnetic phase transition and Mossbauer spectroscopy of ErNi2Mnx compounds(American Institute of Physics, 2011-04-01) Wang, JL; Campbell, SJ; Zeng, R; Dou, SX; Kennedy, SJInvestigation of ErNi(2)Mn(x) with 0.90 <= x <= 1.10 indicates that the MgCu(2)-type structure (with space group Fd-3m) is formed within x = 0.97-1.10. Curie temperature T(C) = 50 K of ErNi(2)Mn is significantly higher than those of the corresponding ErNi(2) (T(C) = 7 K) and ErMn(2) (T(C) = 15 K) compounds. Detailed analyses of DC magnetization data demonstrate that the magnetic phase transition at the Curie temperature is second order. The magnetic entropy change around T(C) has been found to be 4.8 J/kg K for a magnetic field change of 0 to 5 T with its relative cooling power similar to 283 J/kg. (57)Fe Mossbauer spectra below T(C) have been fitted with three sub-spectra representing three inequivalent local magnetic environments while the paramagnetic spectra are fitted using two sub-spectra for two inequivalent crystal sites (8a and 16d), which supports the conclusion based on Rietveld refinement that Mn atoms occupy at both 8a and 16d sites. (C) 2011 American Institute of Physics.
- ItemMagnetic phase transition and thermal expansion in LaFe13-x-yCoySiz(Australian Institute of Physics, 2012-02-02) Wang, JL; Campbell, SJ; Kennedy, SJ; Shamba, P; Zeng, R; Dou, SXThe structural and magnetic properties of a series of LaFe13-x-yCoySix compounds have been investigated by X-ray diffraction, thermal expansion, magnetic and Mössbauer effect measurements. As is evident from the thermal expansion curves of Fig. 1(a), the Curie temperatures of LaFe13-xSix compounds increase with increasing Si content from TC~219 K for x=1.6 to TC~250 K for x=2.6. Further enhancement in the Curie temperature from TC~250 K to TC~281 K is obtained on substitution of Co for Fe in LaFe10.4Si2.6 to LaFe9.4CoSi2.6. A pronounced positive spontaneous volume magnetostriction has been observed below the Curie temperature TC (see Fig. 1(a)). The anomalous thermal expansion can be attributed to the volume dependence of the magnetic energy. Both the magnetization and Mössbauer spectroscopy studies (e.g. Fig. 1(b)) indicate that the type of the magnetic phase transition at TC changes from first order for LaFe11.4Si1.6 to second order for LaFe10.4Si2.6 and LaFe9.4CoSi2.6. The different natures of the magnetic transitions in LaFe13-x-yCoySix are discussed in terms of the classical model for itinerant ferromagnets and the volume dependence of the magnetic energy which is very sensitive to the distance between first-neighbor transition-metal atoms.
- ItemMagnetic phase transitions and entropy change in layered NdMn1.7Cr0.3Si2(AIP Publishing, 2014-01-27) Din, MFM; Wang, JL; Campbell, SJ; Studer, AJ; Avdeev, M; Kennedy, SJ; Gu, QF; Zeng, R; Dou, SXA giant magnetocaloric effect has been observed around the Curie temperature, TC ∼ 42 K, in NdMn1.7Cr0.3Si2 with no discernible thermal and magnetic hysteresis losses. Below 400 K, three magnetic phase transitions take place around 380 K, 320 K and 42 K. Detailed high resolution synchrotron and neutron powder diffraction (10–400 K) confirmed the magnetic transitions and phases as follows: TN intra ∼ 380 K denotes the transition from paramagnetism to intralayer antiferromagnetism (AFl), TN inter ∼ 320 K represents the transition from the AFl structure to the canted antiferromagnetic spin structure (AFmc), while TC ∼ 42 K denotes the first order magnetic transition from AFmc to canted ferromagnetism (Fmc + F(Nd)) due to ordering of the Mn and Nd sub-lattices. The maximum values of the magnetic entropy change and the adiabatic temperature change, around TC for a field change of 5 T are evaluated to be −ΔSM max ∼ 15.9 J kg−1 K−1 and ΔTad max ∼ 5 K, respectively. The first order magnetic transition associated with the low levels of hysteresis losses (thermal <∼0.8 K; magnetic field <∼0.1 T) in NdMn1.7Cr0.3Si2 offers potential as a candidate for magnetic refrigerator applications in the temperature region below 45 K. ©, AIP Publishing LLC.
- ItemMagnetic phase transitions in layered NdMn2Ge2-xSix(Australian Institute of Physics, 2010-02-05) Wang, JL; Campbell, SJ; Cadogan, JM; Studer, AJ; Zeng, R; Dou, SXThe discovery of a giant magnetocaloric effect (GMCE) near room temperature in Gd5Si2Ge2 has led to much attention being paid to layered structures in order to understand the MCE behaviour of such materials [1]. NdMn2Ge2-xSix offers interesting prospects for enhanced magnetocaloric behaviour as the tetragonal, layered structure allows the structural and magnetic states to be controlled via inter- and intra-planar separations of the Mn atoms. We have investigated the structural and magnetic behaviour of NdMn2Ge2-xSix (x=0-2.0) by magnetic measurements, X-ray and neutron diffraction (Wombat, OPAL) over the temperature range 6-465 K. Replacement of Ge by Si leads to contraction of the unit cell with lattice constant a of NdMn2Ge2-xSix passing through two critical values a crit1 and a crit2 in RMn2X2 [2]: a crit1=4.06 Å at x1∼.0 and a crit2=4.02 Å at x∼1.8. This leads to significant modifications of the magnetic states of NdMn2Ge2-xSix. For example, at room temperature both NdMn2Ge1.6Si0.4 and NdMn2Ge1.2Si0.8 are found to exhibit canted ferromagnetism (Fmc) while NdMn2Ge0.8Si1.2 and NdMn2Ge0.4Si1.6 show canted antiferromagnetism (AFmc). By comparison, NdMn2Si2.0 exhibits interlayer antiferromagnetism (AFil) at 300 K [3]. We have established that Fmc and AFmc co-exist for NdMn2Ge1.2Si0.8 between TCNd (9∼0 K) and TNinter (∼180K) while NdMn2Ge0.4Si1.6 has a GMCE value of -∆SMmax=18.4 J kg -1 K -1 around TCNd=36 K for a field change ∆B = 5 T. The overall magnetic behaviours of NdMn2Ge2-xSix compounds are governed by the strong dependence of the magnetic couplings on the Mn-Mn spacing within the ab-plane. A detailed magnetic phase diagram for the NdMn2Ge2-xSix system has been constructed over the entire temperature and composition ranges.
- ItemMagnetic phase transitions in Pr(1-x)LuxMn(2)Ge(2) compounds(Institute of Physics, 2009-03-25) Wang, JL; Campbell, SJ; Studer, AJ; Avdeev, M; Zeng, R; Dou, SXThe effects of replacing Pr by Lu on the magnetic behaviour and structures of Pr1-xLuxMn2Ge2 (x = 0.2, x = 0.4) have been investigated using x-ray diffraction, Mossbauer spectroscopy, magnetization and neutron diffraction measurements. The substitution of Lu for Pr leads to a decrease in the lattice constants a, c and the unit cell volume V at room temperature with this contraction of the unit cell resulting in modifications of the Pr1-xLuxMn2Ge2 magnetic structures. Four and five magnetic phase transitions-linked primarily with temperature driven changes in the intralayer Mn-Mn separation distances-have been detected within the temperature range 4.5-550 K for Pr0.8Lu0.2Mn2Ge2 and Pr0.6Lu0.4Mn2Ge2, respectively, with re-entrant ferromagnetism being detected around T-C(Pr) similar to 31 K for Pr0.6Lu0.4Mn2Ge2. Itwas found that T-C(inter) and T-C(Pr) increase with increasing applied field while T-N(inter) decreases for Pr0.6Lu0.4Mn2Ge2, indicating that the canted antiferromagnetic AFmc region contracts with increasing field. The Debye temperatures for Pr1-xLuxMn2Ge2 with x = 0.2 and 0.4 were evaluated as theta(D) = 320 +/- 40 K and theta(D) = 400 +/- 20 K respectively from the temperature dependence of the average isomer shift. The magnetic structures of both compounds have been determined by means of neutron diffraction measurements over the temperature range 3-300 K with formation of the Fmi magnetic state below Tc/c = 192 K for Pr0.8Lu0.2Mn2Ge2 and the occurrence of re-entrant ferromagnetism below T-C(Pr) = 31 K for Pr0.6Lu0.4Mn2Ge2 being confirmed. © 2009, Institute of Physics
- ItemMagnetic properties and magnetocaloric effect in Mn0.9 Ti 0.1 CoGe(Australian Institute of Physics, 2013-02-06) Wang, JL; Shamba, P; Hutchison, WD; Din, MFM; Avdeev, M; Kennedy, SJ; Campbell, SJ; Zeng, R; Dou, SXNot available
- ItemMagnetic properties and magnetocaloric effect of in layered NdMn1.7V0.2Si2(Australian Institute of Physics, 2013-02-06) Din, MFM; Wang, JL; Zeng, R; Hutchison, WD; Avdeev, M; Kennedy, SJ; Dou, SXNot available
- ItemMagnetic properties and magnetocaloric effect of NdMn2-xTixSi2 compounds(IOP Publishing Ltd, 2013-10-16) Din, MFM; Wang, JL; Campbell, SJ; Zeng, R; Hutchison, WD; Avdeev, M; Kennedy, SJ; Dou, SXThe structural and magnetic properties of the intermetallic compounds NdMn 2− x Ti x Si 2 ( x = 0, 0.1, 0.2, and 0.3) have been studied by x-ray and high resolution neutron powder diffraction, specific heat, dc magnetization, and differential scanning calorimetry measurements over the temperature range 3–450 K. The Curie temperature and Néel temperature of NdMn 2 Si 2 decrease from T C = 36 K and T N = 380 K to T C = 14 K and T N = 360 K, respectively, on substitution of Ti ( x = 0.3) for Mn. The magnetocaloric effect at the first order ferromagnetic phase transition at T C , has been investigated in detail. Under a change of magnetic field of 0–5 T, the maximum value of the magnetic entropy change is 27 J kg −1 K −1 at x = 0, reducing to 15.3 J kg −1 K −1 at x = 0.1 and 10 J kg −1 K −1 at x = 0.3; importantly, no thermal or field hysteresis losses occur (eliminated from 0.3 K and 28.5 J kg −1 at x = 0 around T C ) with increase in Ti concentration. Combined with the lack of any hysteresis effects, these findings indicate that NdMn 1.9 Ti 0.1 Si 2 compound offers potential as a candidate for magnetic refrigerator applications in the temperature region below 35 K. © 2013, IOP Publishing LTD.
- ItemMagnetic properties and magnetocaloric effect of NdMn2−xCuxSi2 compounds(AIP Publishing, 2014-02-19) Din, MFM; Wang, JL; Avdeev, M; Gu, QF; Zeng, R; Campbell, SJ; Kennedy, SJ; Dou, SXStructural and magnetic properties of NdMn2−x Cu xSi2 compounds (x = 0–1.0) have been investigated by high intensity x-ray and resolution neutron diffraction (3–450 K), specific heat, dc magnetization, and differential scanning calorimetry measurements. Substitution of Cu for Mn leads to an increase in the lattice parameter a but a decrease in c at room temperature. Two magnetic phase transitions have been found for NdMn2−x Cu xSi2 compounds with TN for the antiferromagnetic ordering of Mn-sublatttice and TC for the Nd-sublattice ferromagnetic ordering, respectively. TC increases significantly with increasing Cu content from 36 K at x = 0 to 100 K at x = 1.0. Moreover, it is found that the order of magnetic phase transition around TC also changes from first order at x < 0.6 to second order transition for x ≥ 0.6. The spontaneous magnetization found to decrease with the increase in Cu concentration which can be understood in the term of the dilution effect of Cu for Mn. The values of −ΔSM around TC decrease with increasing x from 27 J kg−1 K−1 for x = 0 to 0.5 J kg−1 K−1 for x = 1.0 under 0–5 T field. Refinement of neutron diffraction patterns for x = 0.2 confirms the magnetic states detected by magnetic study and also indicates that the lattice constants a and c show a distinct variation around TC. © 2014, AIP Publishing LLC.
- ItemMagnetic properties in polycrystalline and single crystal Ca-doped LaCoO3(American Physical Society, 2011-04-01) Zeng, R; Debnath, JC; Chen, DP; Shamba, P; Wang, JL; Kennedy, SJ; Campbell, SJ; Silver, T; Dou, SXPolycrystalline (PC) and single crystalline (SC) Ca-doped LaCoO3 (LCCO) samples with the perovskite structure were synthesized by conventional solid-state reaction and the floating-zone growth method. We present the results of a comprehensive investigation of the magnetic properties of the LCCO system. Systematic measurements have been conducted on dc magnetization, ac susceptibility, exchange-bias, and the magnetocaloric effect. These findings suggest that complex structural phases, ferromagnetic (FM), and spin-glass/cluster-spin-glass (CSG), and their transitions exist in PC samples, while there is a much simpler magnetic phase in SC samples. It was also of interest to discover that the CSG induced a magnetic field memory effect and an exchange-bias-like effect, and that a large inverse irreversible magnetocaloric effect exists in this system.(C) 2011 American Institute of Physics. [doi:10.1063/1.3562518]
- ItemMagnetic properties of Ho2Fe17-xMnx - influence of Mn substitution(Institute of Physics, 2009-07-26) Wang, JL; Campbell, SJ; Studer, AJ; Kennedy, SJ; Zeng, RThe structural and magnetic properties of Ho2Fe17−xMnx (x=0−5) have been investigated by x-ray diffraction, Mössbauer spectroscopy and DC magnetization measurements (0-5 T) over the temperature range 4.5–350 K. Similar to other ferrimagnetic R2Fe17−xMnx systems, the unit cell volume generally increases with Mn content other than for low Mn values where a slight maximum is detected around x ~ 0.5. The nature of the magnetic phase transitions around TC is shown by Arrot plot analysis to be second order for all samples. The Curie temperature remains essentially unchanged for Mn contents up to x=1.0 (TC = 336 K for x=0.0, TC = 338 K for x=1.0) before decreasing steadily with further increase in Mn content (TC = 209 K for x=5). The 57Fe hyperfine interaction parameters have been determined from variable temperature Mössbauer spectra.
- ItemMagnetic structures and magnetovolume effects in Ho2Fe17-xMnx(Australian Institute of Physics, 2009-02-04) Wang, JL; Campbell, SJ; Studer, AJ; Kennedy, SJ; Zeng, R; Dou, SXNot available
- ItemMagnetic structures of Pr0.8Lu0.2Mn2Ge2 and Pr0.6Lu0.4Mn2Ge2(Institute of Electrical and Electronics Engineers (IEEE), 2011-10-01) Wang, JL; Studer, AJ; Campbell, SJ; Kennedy, SJ; Zeng, R; Dou, SX; Wu, GHThe magnetic structures of Pr0.8Lu0.2Mn2Ge2 and Pr0.6Lu0.4Mn2Ge2 have been determined by neutron powder diffraction over the temperature range 10-450 K. On cooling from the paramagnetic region the Mn sublattice of Pr0.8Lu0.2Mn2Ge2 orders in a similar manner to PrMn2Ge2 with first ab-plane intralayer antiferromagnetism (AFl) below TNintra ~ 397 K followed by canted ferromagnetism (Fmc) at TCinter ~ 330 K and then a conical (Fmi) spin structure below Tc/c ~ 192 K. The transition at TCPr=35 K with related enhancement in magnetization, is assigned to the additional ferromagnetic contribution of the Pr sublattice leading to the combined (Fmc+F(Pr)). For Pr0.6Lu0.4Mn2Ge2 the transition from PM to AFl occurs at TNintra ~ 375 K while the canted ferromagnetic (Fmc) state forms at TCinter ~ 321 K . The increased Lu concentration of Pr0.6Lu0.4Mn2Ge2 destroys the incommensurate Fmi conical spin structure of Pr0.8Lu0.2Mn2Ge2. Rather, in common with similar mixed RT2X2 systems (e.g., La1-xYxMn2Si2, La1-xPrxMn2Si2), the Pr0.6Lu0.4Mn2Ge2 compound exhibits co-existence of the AFmc and Fmc phases on cooling from the pure Fmc state. Transformation to the combined ferromagnetic state (Fmc+F(Pr)) takes place on c-axis ordering of the Pr sublattice at TCPr ~ 31 K . In the region of phase co-existence, the Fmc unit cell is larger than the AFmc unit cell indicating strong magneto-structural coupling with a chan- - ge of the lattice inducing a change of the magnetic state. © 2011, Institute of Electrical and Electronics Engineers (IEEE)