Low temperature magnetic properties of NdxCo1− x amorphous thin films

• Published in: Journal of magnetism and magnetic materials Vol. 58; no. 3; pp. 273 - 279
• Main Authors: Rei-Yi, Fang, Dao-sheng, Dai, Zun-xiao, Lui, Hong, Wan, Yu-ping, JI
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.1986; Elsevier Science
• Subjects: Analysing. Testing. Standards; Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of surface, thin films and multilayers; Materials science; Measurement of properties and materials state; Metals, semimetals and alloys; Metals. Metallurgy; Nondestructive testing; Physics; Specific materials; Magnetization; Temperature effect; Composition effect; Lanthanide Alloys; Very low temperature; Amorphous alloy; Experimental study; Thin film; Transition metal Alloys; Vapour deposition; Exchange interaction; Magnetic structure; Chemical composition; Molecular field approximation; Binary alloy; Low temperature
• ISSN: 0304-8853
• DOI: 10.1016/0304-8853(86)90447-6

Amorphous thin films of Nd x Co 1− x alloys were prepared over the composition range 0.07 ⩽ x ⩽ 0.96 by the vacuum evaporation method with two heating sources. The field dependence of magnetization σ( H) in 0–7 T and at 1.5 K for all samples were investigated. The magnetic structure of these films were studied by magnetic measurement. It was found that the effective magnetic moment of the Co atom μ Co = 1.87 ƒ(x)μ B, ƒ(x) being the probability for bearing magnetic moment of cobalt atoms, the effective magnetic moment of the Nd atom μ Nd = 2.28μ B for 0.07 ⩽ x ⩽ 0.50, and μ Nd = 2.28 - 1.76 (x − 0.50) for 0.50 ⩽ x ⩽ 0.96, and the maximum distribution angle ψ O of magnetic moment of neodymium atoms is about 66° at x < 0.50 and ψ O = 66° + 63.3° ( x − 0.50) at x ⩾ 0.50. The temperature dependence of the magnetization σ( T) at 1.5−200 K with H = 7.0 T has been measured. When the neodymium concentration is larger than 24 at %, there is a sudden drop of σ( T) at about 20 K, and this temperature does not change with increase of Nd component. The results show that the demagnetized state of the amorphous Nd-Co films may be composed of asperomagnetic and speromagnetic structures. The sudden drop of σ( T) near 20 K for samples with x ⩾ 0.24 may be explained by the phase transition between speromagnetism and paramagnetism.