Abstract

Amorphous Fe_xZr_100−x alloys display a complex magnetic phase diagram, particularly in the range 89% ≲ x ≲ 93% in which the phase transition from the paramagnetic to a soft ferromagnetic (FM) state at a critical temperature T_c precedes a second transition at T_xy < T_c to a transverse spin-glass (SG) phase, with frozen spin components transverse to the magnetization. The softness of the FM phase and the coexistence of FM and SG orderings complicate exploring the low-temperature and low-field critical properties of the glassy transition. Here we study the irreversibility Almeida-Thouless (AT) line that marks the onset of the transverse SG phase in the Fe₉₀Zr₁₀ alloy in the low-field regime up to H = 60 Oe. While ZFC measurements give rise to an AT exponent ϕ = 4.6, similar to that of another amorphous FM compound with random local anisotropy, the induction of magnetic shiftings upon cooling the sample in a large field, − 85 kOe, displaces down the AT line and separates it into two distinct regimes: one also with ϕ = 4.6 for H above 20 Oe, nearly corresponding to the typical field to flip the remanent magnetization, and a new second regime at lower H, with field-induced remanent clusters and exponent ϕ = 3.6 that approaches the mean-field value ϕ = 3. Our findings are discussed on the light of the results from a random nonuniform anisotropy model with FM exchange interactions, which also reported the existence of a two-regimes scenario in the AT line with similar exponents.

Graphical abstract

中文翻译：

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Fe 90 Zr 10非晶态合金横向成分自旋玻璃相低场不可逆线的研究

摘要

Fe _x Zr _{100- x}非晶态合金显示出复杂的磁相图，特别是在89％x x 93％的范围内，其中临界温度T _c下从顺磁性到软铁磁性（FM）的相变先于a T _xy < T _c处的第二次跃迁到旋转自旋玻璃（SG）相，冻结的自旋分量垂直于磁化强度。FM相的柔软性以及FM和SG顺序的共存使探索玻璃态转变的低温和低场临界特性变得复杂。在这里，我们研究了不可逆的Almeida-Thouless（AT）线，该线标志着在低磁场条件下（H = 60 Oe）Fe ₉₀ Zr ₁₀合金中横向SG相的开始。ZFC测量产生AT指数on= 4.6，类似于另一种具有随机局部各向异性的无定形FM化合物，在大范围内冷却样品时的磁位移感应-85 kOe，将AT线向下移动并将其分为两个不同的状态：φ = 4.6 Ĥ以上20奥斯特，几乎对应于典型的场翻转剩磁，并且在较低的新的第二方案ħ，与场致剩余集群和指数φ = 3.6而接近平均场值φ =3。我们的结果是根据具有FM交换相互作用的随机非均匀各向异性模型的结果进行讨论的，该模型还报告了在AT线中存在两种具有相似指数的方案的情况。

图形概要