Unconventional critical behavior in the weak ferromagnet BaIrO3T. Kida1, A. Senda1, S. Yoshii1, M. Hagiwara1, T. Takeuchi2, T. Nakano3, 4 and I. Terasaki3, 4
1 KYOKUGEN, Osaka University - 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
2 Low Temperature Center, Osaka University - 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
3 Department of Applied Physics, Waseda University - 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
4 CREST, Japan Science and Technology Agency - Kawaguchi, Saitama 332-0012, Japan
received 7 May 2008; accepted in final form 4 September 2008; published October 2008
published online 2 October 2008
We report the results of ac/dc magnetization study of the critical behavior in a weak ferromagnet BaIrO3. The critical temperature has been determined to be = 182.8 K by the ac susceptibility measurement. We have analyzed our dc magnetization data near with the help of the modified Arrott plot method. The critical exponents have been determined to be = 0.820.03, = 1.030.03, and = 2.200.01, which roughly obeys . Using these values of , , and , we find that each magnetization-field-temperature (M-H-T) behavior below and above obeys a scaling relation, following a single equation of state in which is uniquely related to where . These findings demonstrate that the ferromagnetic transition in BaIrO3 belongs to a new universality class of the second-order phase transition.
75.40 Cx - Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.).
75.60.Ej - Magnetization curves, hysteresis, Barkhausen and related effects.
71.30.+h - Metal-insulator transitions and other electronic transitions.
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