Anisotropic magnetoresistivity and magnetic entropy change in HoAl2

Abstract We report a correlation between magnetoresistivity Δρ mag and magnetic entropy change ΔS mag for specified crystallographic directions of a HoAl 2 single crystal. This ferromagnetic compound shows differentiated behavior among the members of the RAl 2 series due to the presence of spontaneous spin reorientation. We discussed this effect in order to establish a relationship between the two quantities studied. The calculations were performed using a self-consistent model based on a Hamiltonian containing exchange, Zeeman and crystal field terms. We found that the normalized relation { Δρ mag } = ( T / T C ) m { ΔS mag }, with m  = 0.1 for the [100] and [110] directions matches satisfactorily the two quantities.