Specific heat of La(Fe0.873Co0.007Al0.12)13 compound in antiferromagnetic and ferromagnetic states

The low-temperature specific heat Cp of La(Fe0.873Co0.007Al0.12)13 compound has been measured in two states: (i) antiferromagnetic (AFM) with a Neel temperature of TN = 192 K and (ii) ferromagnetic (FM). The FM order appears at T = 4.2 K in a sample exposed to an external magnetic field with induction BC ≥ 2.5 T and is retained for a long time in a zero field at temperatures up to T*C = 23 K. The coefficient γFM in the low-temperature specific heat C = γT + βT3 in the FM state differs quite insignificantly from that (γAFM) in the AFM state. Contributions to the low-temperature specific heat, which are related to a change in the elastic and magnetoelastic energy caused by magnetostrictive deformations, are considered