Rare Earth Intermetallic Compounds with a Huge Magnetostriction and Compensated Magnetic Anisotropy
S.Nikitin, I.S.Tereshina, A.P.Touliakov (Faculty of Phisics, Moscow State University, Moscow, Russia); Yu.B.Patrikeev, T.G.Sochenkova (GIREDMET, Moscow, Russia)
In the last decade there has been an ever increasing interest in the development of materials having largest possible magnetostrictive deformations in technically warranted magnetic fields. The present work was intended to study the magnetostriction in alloys with compensated magnetic anisotropy having cubic crystal lattice of the Laves phase type with a stoichiometry R[Z]R'[1-Z]Fe[2-X]Co[X], where R and R’ are rare earth ions with single ion magnetic anisotropy constants of opposite sign and where iron was replaced by cobalt. The chief purpose of the investigation was to determine the compositions having large magnetostriction in the external field region H = 0.5 – 5 kOe. Two intermetallic systems were studied, (Tb[0.75]Ho[0.25])[0.5]Dy[0.5]Fe[2-X]Co[X] and Tb[0.27]Dy[0.73]Fe[2-X]Co[X]. The alloys were arc melted in argon at a temperature Ò = 1480Ñ on a water-cooled bottom plate in a furnace with a non-consumable tungsten electrode. In a number of compositions a change of the sign and an abrupt increase of the longitudinal magnetostriction with temperature was found and associated with the spin-reorientation phase transition. The data obtained show that a number of compositions exhibit magnetostriction characteristics higher than in Terfenol (Tb[0.27]Dy[0.73]Fe compounds). It was found that in some cobalt-substituted alloys the magnetostriction is higher than in initial non-substituted compositions.
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