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Lecture Mufti Nadang

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WanneerWaar
12 januari 2010 FWN-Building 5114.0004, Nijenborgh 4, 9747 AG, Groningen
Speaker: Dr. Mufti Nandang
Affiliation: Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany
Title: Magnetic properties of YbCo2Si2 studied by neutron diffraction
Date: Tue Jan 12, 2010
Start: 14.00
Location: FWN-Building 5114.0004
Host: T.T.M. Palstra
Telephone: +31 50 363 4419

Abstract

While for most rare earth element R magnetic ordering in RT2X2 (T= transition metal and X = Si, Ge) has been thoroughly investigated, only very few results are available for Yb homologous. In this context YbCo2Si2 is very interesting because it is isoelectronic to quantum critical system of YbRh2Si2. It preset a stable Yb3+ state which show magnetic ordering at 1.7 K. We recently grew single crystals and started an extensive study of the magnetic properties of this compound. Magnetic susceptibility, specific heat, and electrical resistivity results evidenced a pronounced easy plane anisotropy and two magnetic transitions at TN ~ 1.7 K and TL ~ 0.9 K. Magnetization, susceptibility and magnetoresistance measurements indicate a complex B-T phase diagram with some anisotropy in the basal plane. Here, we will present the results of our investigation with single crystal and powder neutron diffractions in absence and under magnetic field up to 2.5 T.  A commensurate magnetic structure with q = (0.25, 0.25, 1) and incommensurate magnetic structure with q= (0.25, 0.08, 1) are observed for the ground state and intermediate phase, respectively. The critical exponent b for TN is obtained as b   = 0.369 + 0.03 which is close to the expected value of 3D Heisenberg system. We shall propose a magnetic structure for both ordered phases.

Laatst gewijzigd:22 oktober 2012 14:31