Butterfly-like specific heat, magnetocaloric effect and itinerant metamagnetism in (Er,Y)Co2 compounds
- Institute of Metal Physics, Russia
- Helmholtz-Zentrum Berlin
- Hahn-Meitner Institut, Berlin, Germany
- ORNL
- Ural State University, Russia
The field-induced first-order phase transition in (Er{sub 1-x}Y{sub x})Co{sub 2} with the yttrium concentration x = 0.45 is observed to be accompanied by a butterflylike behavior and significant irreversibility of the specific heat. The coefficient {gamma} of the T-linear specific heat decreases by {approx}48% under application and removal of a magnetic field up to 20 kOe. This behavior is attributed to the itinerant electron metamagnetism of Co 3d electrons. The isothermal magnetic entropy change {Delta}S{sub m} in Er{sub 0.55}Y{sub 0.45}Co{sub 2} includes a large contribution associated with spin fluctuations induced by the f-d exchange interaction in the hybridized 3d-5d-electron subsystem. These spin fluctuations are suggested to contribute substantially to the magnetocaloric effect of the RCo{sub 2} type compounds. The maximal {Delta}S{sub m} value observed for ErCo{sub 2} just above the Curie temperature is ascribed to the closeness of the T{sub c} value to the spin-fluctuation temperature T{sub sf} of itinerant Co 3d electrons. The nonmonotonous change in {Delta}S{sub m} with the Curie temperature of R{sub 1-x}R{sub x}{prime}Co{sub 2} compounds is explained by the temperature variation in the spin-fluctuation contribution to the magnetocaloric effect.
- Research Organization:
- Oak Ridge National Laboratory (ORNL)
- Sponsoring Organization:
- SC USDOE - Office of Science (SC)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 979129
- Journal Information:
- Physical Review B, Journal Name: Physical Review B Journal Issue: 18 Vol. 79; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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