Thermal, Electrical, and Magnetic Properties of the Amorphous Alloys RExSi1–x (RE = Gd or Tb;x = 0.87, 0.59, 0.18)

Abstract

The RExSi1–x alloys are elaborated for three eutectic compositions. They are studied by ATD, electrical, and magnetic measurements. These alloys exhibit a good thermal stability, an important atomic relaxation, and a two‐step crystallization to attain the crystalline alloys located on each side of the eutectic. The RE‐rich alloys have a metallic or nearly metallic behaviour; the RE‐poor alloys present a semiconductor‐like conductivity. It is impossible to say if there is a magnetic order at low temperature for small x. On the contrary the asperomagnetic order is evident for RE‐rich alloys. The thermal behaviour of the magnetization in weak field is similar to that for the other parameters (coercive field, remanent magnetization, loop energy, field saturating the loop) characterising the hysteresis loop.

Spin-Glass Freezing and RKKY Interactions near the Metal-Insulator Transition in Amorphous Gd-Si Alloys

“…Table I shows that the effective moment p and u are largest for samples near the MI transition (x 0.12 and 0.14), and drop significantly for x 0.07 and 0.036, which are strongly insulating. p is also suppressed for x 0.19, consistent with the results reported in the literature of reduced moments at this composition [5,13]. This nontrivial dependence of x on composition is easily seen in 1͑͞x dc ͞n Gd ͒ in Fig.…”

“…For x , 0.5, T c drops precipitously to zero and the induced magnetization at 4.2 K drops well below a simple local moment model [5]. Measurements of a-Gd 0.18 Si 0.82 showed signs of antiferromagnetic 0031-9007͞00͞84(23)͞5411(4)$15.00 interactions at low temperature (a Curie-Weiss intercept of 210 K, and a large high field susceptibility), but no magnetic freezing was claimed [13].…”

Metal–insulator transition in amorphous alloys

“…This subject has been investigated so intensively that it is impossible to give here a complete survey of all related studies of structure and transport properties of amorphous alloys in the vicinity of the MIT. Thus the following selection, listed according to the alloys investigated, contains merely the more important publications on low-temperature transport and, in some cases, structure: Ge-Al [27], Ge-Au [28][29][30], Ge-Co [31], Ge-Cu [32], Ge-Cr [31,[33][34][35], Ge-Fe [31,[36][37][38][39][40], Ge-Mn [31], Ge-Mo [40,41], Ge-Ni [31], Si-Au [42][43][44][45][46][47], Si-Cr [35,[48][49][50][51][52][53][54][55][56][57], Si-Fe [38,58,59], Si-Gd [60,61], Si-Mn [58,[62][63][64], Si-Nb …”

Metal–insulator transition in amorphous alloys

“…This subject has been investigated so intensively that it is impossible to give here a complete survey of all related studies of structure and transport properties of amorphous alloys in the vicinity of the MIT. Thus the following selection, listed according to the alloys investigated, contains merely the more important publications on low-temperature transport and, in some cases, structure: Ge-Al [27], Ge-Au [28][29][30], Ge-Co [31], Ge-Cu [32], Ge-Cr [31,[33][34][35], GeFe [31,[36][37][38][39][40], Ge-Mn [31], Ge-Mo [40,41], Ge-Ni [31], Si-Au [42][43][44][45][46][47], Si-Cr [35,[48][49][50][51][52][53][54][55][56][57], Si-Fe [38,58,59], Si-Gd [60,61], Si-Mn [58,[62][63][64], Si-Nb …”