Structural, magnetic and magnetostrictive properties of Tb_0.2Pr_0.8(Fe_0.4−xCo_0.6+x)_1.93alloys

Abstract

Structural, magnetic and magnetostrictive properties of Tb0.2Pr0.8(Fe0.4−xCo0.6+x)1.93 (0 ⩽ x ⩽ 0.2) alloys have been investigated by means of x-ray diffraction, ac initial susceptibility, a superconducting quantum interference device magnetometer and a standard strain gauge technique. A single (Tb, Pr)(Fe, Co)2 Laves phase with a cubic MgCu2-type structure is formed when 0.05 ⩽ x ⩽ 0.2. Increasing the Co content in the Tb0.2Pr0.8(Fe0.4−xCo0.6+x)1.93 alloys reduces the magnetocrystalline anisotropy constant K1 and improves the magnetostrictive properties at relatively low magnetic fields at room temperature. The Tb0.2Pr0.8(Fe0.35Co0.65)1.93 alloy with a single Laves phase has a spontaneous magnetostriction λ111 as high as 1900 ppm, a large magnetostriction λa (= λ∥ − λ⊥) at a relatively low magnetic field and a large λa/K1, and may make it a promising magnetostrictive material.

Magnetic properties of nickel hydroxide nanoparticles

“…In magnetic nanoparticles system, the surface spins may be frozen at low temperatures. [5][6][7]26,27 Similarly, the exchange interaction between the surface spins and core moments occurs, leading to the exchange bias field in Ni͑OH͒ 2 nanoparticles. Moreover, from XPS analysis in Fig.…”

“…[1][2][3][4][5][6][7][8][9][10][11] The exchange-bias phenomenon, i.e., the hysteresis loop shifts in the applied field, was first discovered by Meiklejohn and Bean in oxide-coated Co particles. 12 Recently, the research on the exchange bias has been attractive, because of its fundamentally important role in spin valve and tunneling devices.…”

High magnetostriction at low fields of epoxy/Tb1−xPrx(Fe0.4Co0.6)1.9 composites

“…It can be interpreted in terms of that the anisotropy of the alloys increases and hence the domain-wall pinning should be more pronounced with increasing the Tb content, attributed to the much larger anisotropy of Tb 3+ ion than that of Pr 3+ ion [14]. A threshold field was also observed in the magnetic field dependence of magnetoelastic properties such as magnetostriction, and relative change in elastic modulus E for the magnetostrictive compound with large anisotropy, whereas no threshold field was observed for the ones with small anisotropy [15,16]. The magnetization at the field of 7.5 kOe increases with increasing the Pr-content, since the magnetic moment of praseodymium (or terbium) aligns parallel (or antiparallel) with the moment of iron/cobalt in the rare earth-transition-metal compounds.…”

Structure and anisotropic compensation of Tb1−xPrx(Fe0.4Co0.55B0.05)1.93 (0≤x≤1) magnetostrictive alloys

“…Recently, new progresses were attained by introducing B/Co as interstitial/substitutional atoms into the Pr-containing compounds, stabilizing the formation of Laves phase under ambient condition [8,9]. Ren the partial substitution of Co for Fe can effectively prevent the appearance of the secondary phase [9].…”