Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 13: Magnetic Materials II

MA 13.1: Talk

Monday, March 14, 2011, 17:00–17:15, HSZ 401

Evidence of a new magnetic configuration in ferrimagnets RCo₂ — •Julia Herrero-Albillos¹, Marcela Bonilla², Luis Miguel García Vinuesa², Fernando Bartolomé², Celia Castán², Noelia Marcano², and Irene Calvo² — ¹Helmholtz-Zentrum Berlin, Albert Einstein strasse 15, 12489 Berlin (Adlershof), Germany — ²Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain.

Different experimental techniques allowed us to identify a new magnetic configuration within the paramagnetic phase of ferrimagnet ErCo₂. In this new magnetic ordering, coined as parimagnetism,[1] the Co net magnetic moment is aligned antiparallel to the Er and to the applied field at temperatures well above T_C and below certain flipping temperature. Magnetic short-range correlations of Co atoms within the parimagnetic state have been also established by means of small angle neutron scattering measurements. Thermopower and µSR spectroscopy measurements give also evidence about the existence of these strong correlated magnetic entities. Recently analysis carried on X-ray magnetic circular dichorism (XMCD) spectra taken in HoCo₂ and DyCo₂ have showed also the antiparallel arrangement of Co net magnetic moment respect to the rare earth in both compounds. The XMCD measurements allow us to propose a new magnetic phase diagram, for ErCo₂, HoCo₂ and DyCo₂. These results suggest that parimagnetism is a more general phenomenon among this ferromagnetic family. [1] J. Herrero-Albillos, et al., Physical Review B 76, 2007.