Magnetic oscillation of crystal without spontaneous moment caused by single-ion anisotropy achieved by a horseshoe magnet above 1000K

Abstract Temperature dependence of anisotropy of magnetic susceptibility Δ χ was studied up to T =1000 K for various oxide crystals using a method based on field-induced rotational-oscillation of a sample; Δ χ – T relationships followed the Curie–Weiss law for muscovite, talc, Mg(OH) 2 , Al(OH) 3 , AlOOH orthoclase and corundum. The Δ χ -values are above 10 −7 emu/g at T =1000 K for many of the measured oxides; spontaneous magnetic moments due to spin ordering are usually lost at this temperature. This magnitude of Δ χ is large enough for micro-crystals, which are dispersed in fluid medium, to be aligned below B =1 T that can be produced by a permanent magnet. Alignment at low field intensity is effective to extend various field-induced materials processing at high temperatures, for example, crystal growth of high quality.