Eur. Phys. J. B (2012) 85: 71
https://doi.org/10.1140/epjb/e2011-20807-4

Regular Article

Field-induced valence transition in EuPtP_1−xAs_x

¹ Department of Physics, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, 812-8581 Fukuoka, Japan
² Institute for Solid State Physics, University of Tokyo, Kashiwanoha, 277-8581 Kashiwa, Japan

^a e-mail: 3da@phys.kyushu-u.ac.jp

Received: 3 October 2011
Received in final form: 10 December 2011
Published online: 20 February 2012

Abstract

The ternary compound EuPtP exhibits two valence transitions at T₁ = 235 K and T₂ = 190 K. In order to examine a field-induced valence transition of Eu, we synthesized EuPtP_1−xAs_x compounds with 0.05 ≤ x ≤ 0.5 and studied the magnetic and valence behavior. The substitution of As for P increases the lattice volume linearly and decreases both valence transition temperatures, T₁ and T₂, in contrast to the behavior under external pressures. The magnetization process in a pulsed magnetic field revealed that EuPtP_0.5As_0.5 exhibits an onset of metamagnetic transition above 50 T with a large hysteresis, which evidences a first-order field-induced valence transition. The analysis of the magnetization curves of x = 0.5 at various temperatures has demonstrated that the field-induced transition is essentially the same as the transition induced by temperature at T₁.