The effects of Cu substitution on magnetocaloric effects of the HoCo1−xCuxSi (0 ≤ x ≤ 0.4) phases

Abstract

By hetero-structural alloying ferromagnetic (FM) TiNiSi-type orthorhombic HoCoSi with antiferromagnetic (AFM) Ni2In-type hexagonal HoCuSi, the magnetic and structural evolutions have been observed in HoCo1−xCuxSi (0 ≤ x ≤ 0.4) alloys. The magnetic property is changed from ferromagnetic for x ≤ 0.3 to antiferromagnetic for x = 0.4 in HoCo1−xCuxSi system. With the field change Δμ0H = 5 T, the maximum magnetic entropy changes (−ΔSMmax) are 10.1 J kg−1 K−1, 8.6 J kg−1 K−1, 7.6 J kg−1 K−1, 10.0 J kg−1 K−1 and 13.6 J kg−1 K−1 in HoCo1−xCuxSi (x = 0, 0.1, 0.2, 0.3 and 0.4) alloys, respectively. With the enhancement of substitution amount, the −ΔSMmax is decreased for x ≤ 0.2, which is caused by magnetic moment dilution effects. But the −ΔSMmax is increased for 0.3 ≤ x ≤ 0.4, which is caused by the field-induced metamagnetic transition at the critical component.