I. O. Troyanchuk,1,* D. V. Karpinsky,1,2 M. V. Bushinsky,1 V. A. Khomchenko,3 G. N. Kakazei,4,5 J. P. Araujo,4 M. Tovar,6 V. Sikolenko,7,8 V. Efimov,7 and A. L. Kholkin2 1Scientific-Practical Materials Research Centre (SSPA) of NAS of Belarus, P. Brovka str. 19, BY-220072 Minsk, Belarus 2CICECO/Department of Ceramics and Glass Engineering, University of Aveiro, PT-3810-193 Aveiro, Portugal 3CEMDRX/Department of Physics, Faculty of Sciences and Technology, University of Coimbra, PT-3004-516 Coimbra, Portugal 4IFIMUP/Department of Physics, Faculty of Sciences, University of Porto, PT-4169-007 Porto, Portugal 5Institute of Magnetism, NAS of Ukraine, 36 b Vernadskogo Boulevard, UA-03142 Kiev, Ukraine 6Helmholtz-Zentrum-Berlin for Materials and Energy, DE-14109 Berlin, Germany 7Joint Institute for Nuclear Research, Dubna, RU-141980 Russia 8Paul Scherrer Institute, CH-5232 Villigen, Switzerland (Received 27 October 2010; revised manuscript received 12 January 2011; published 22 February 2011)