ESR studies of magnetocaloric PrMn2-xFexGe2

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Australian Institute of Physics
In a recent paper, we investigated the magnetic structures, phase transitions and magnetocaloric entropy of PrMn1.6Fe0.4Ge2 by a combination of bulk magnetometry, 57Fe Mössbauer spectroscopy and electron spin resonance (ESR) over the temperature range 5-300 K. This work followed on from a broader study of the PrMn2-xFexGe2 family of compounds, in which it was found that with decreasing temperature from the paramagnetic region, three magnetic phase transitions have been detected for PrMn1.6Fe0.4Ge2. The transition temperatures and related magnetic structures (using the notation of [3]) the magnetic structures are: (i) paramagnetism to intralayer antiferromagnetism (AFl) at TN intra=370 K; (ii) AFl to canted ferromagnetism (Fmc) at TC inter∼230 K, and (iii) a third transition around TC Pr∼30 K with ferromagnetic ordering of the Pr sublattice resulting in the combined magnetic region (Fmc+F(Pr)). Here the ESR, focusing on the Pr3+ 4f magnetic moment and undertaken in the vicinity of the lowest transition temperature, is the subject of further analysis in order to correlate the observed resonant line/s and changes in g-factors with the phases mentioned above. In particular an aim is to link the increase in g factor of the Pr3+ ion (from g = 0.85 in the region above TC Pr∼30 K to g ~ 2.5 at 8 K) with the bulk moments measured via DC magnetisation.
Elements, Magnetic resonance, Metals, Physical properties, Rare earths, Thermodynamic properties, Transition elements
Ren, Q. Y., Hutchison, W. D., Campbell, S. J., & Wang, J. L. (2014). ESR studies of magnetocaloric PrMn2-xFexGe2. Poster presented to the 38th Annual Condensed Matter and Materials Meeting 2014, Waiheke Island Resort, Waiheke, Auckland, New Zealand; 4th February - 7th February, 2014. Retrieved from: