Eur. Phys. J. B (2013) 86: 489
https://doi.org/10.1140/epjb/e2013-30968-7

Regular Article

Short-range magnetic correlations and parimagnetism in RCo₂^*

¹ Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC - Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
² Fundación ARAID, Paseo María Agustín 36, 50004 Zaragoza, Spain
³ Centro Universitario de la Defensa, Carretera de Huesca s/n, 50090 Zaragoza, Spain
⁴ Institut Laue-Langevin, 38042 Grenoble, France
⁵ Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
⁶ Ames Laboratory, U.S. Department of Energy, Iowa State University, Ames, Iowa 50011-3020, USA
⁷ Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011-2300, USA

^a e-mail: bartolom@unizar.es

Received: 23 October 2012
Received in final form: 25 May 2013
Published online: 2 December 2013

Abstract

X-ray circular magnetic dichroism, polarized neutron diffraction, ac susceptibility, and Seebeck effect have been measured for several members of the RCo₂ series (R = Ho, Tm, Er) as a function of temperature and applied magnetic field. The experimental results show robust parimagnetism (a general behaviour along the RCo₂ series with R being a heavy rare earth ion) and two reversal temperatures in some systems, which is an unexpected result. Polarised neutron diffraction show differences between results obtained on single crystals or polycrystalline ingots. We propose an interpretation of parimagnetic RCo₂ as a Griffiths phase of the high temperature, magnetically ordered, amorphous RCo₂ phase.