Magnetic entropy change and accurate determination of Curie temperature in single-crystalline helimagnet FeGe
1 Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
2 Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences - Hefei 230031, China
Received: 15 March 2017
Accepted: 17 March 2017
Cubic helimagnet FeGe has emerged as a class of skyrmion materials near room temperature that may impact future information technology. Experimentally identifying the detailed properties of skyrmion materials enables their practical application acceleratedly. Here we study the magnetic entropy change (MEC) of single-crystalline FeGe in its precursor region and clarify its close relation to the critical exponents of a second-order phase transition in this area. The maximum MEC is found to be 2.86 J/kg · K for a 7.0 T magnetic-field change smaller than that of common magnetocaloric materials indicating the multiplicity and complexity of the magnetic structure phases in the precursor region. This result also implies that the competition among the multimagnetic phases can partly counteract the magnetic-field–driven force and establishes a stable balance. Based on the obtained MEC and the critical exponents, the exact Curie temperature of single-crystalline FeGe under zero magnetic field is confirmed to be 279.1 K, higher than the previously reported 278.2 K. This finding paves the way for reconstruction of the FeGe phase diagram in the precursor region.
PACS: 75.30.Kz – Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.) / 75.30.Sg – Magnetocaloric effect, magnetic cooling / 75.70.Kw – Domain structure (including magnetic bubbles and vortices)
© EPLA, 2017