Temperature-dependent conduction-band exchange splitting in ferromagnetic hcp gadolinium : theoretical predictions and photoemission experiments

• Published in: Physical review letters Vol. 68; no. 12; pp. 1931 - 1934
• Main Authors: BONGSOO KIM, ANDREWS, A. B, ERSKINE, J. L, KWANG JOO KIM, HARMON, B. N
• Format: Journal Article
• Language: English
• Published: Ridge, NY American Physical Society 23-03-1992
• Subjects: 360104 - Metals & Alloys- Physical Properties; ANGULAR DISTRIBUTION; Applied sciences; BINDING ENERGY; Condensed matter: electronic structure, electrical, magnetic, and optical properties; CURIE POINT; DISTRIBUTION; ELECTRON SPECTROSCOPY; Electron states; ELECTRONIC STRUCTURE; ELEMENTS; ENERGY; Exact sciences and technology; EXCHANGE INTERACTIONS; FERROMAGNETIC MATERIALS; GADOLINIUM; INTERACTIONS; Level splitting and interactions; MAGNETIC MATERIALS; MATERIALS; MATERIALS SCIENCE; METALS; Metals. Metallurgy; PHOTOELECTRON SPECTROSCOPY; PHYSICAL PROPERTIES; Physics; RARE EARTHS; SPECTROSCOPY; TEMPERATURE DEPENDENCE; THERMODYNAMIC PROPERTIES; TRANSITION TEMPERATURE; Lanthanide; Ultraviolet radiation; Temperature; Exchange interaction; Paramagnetic materials; Ferromagnetic materials; Band splitting; Gadolinium; Photoelectron emission; Valence band; Experimental study; Low temperature
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.68.1931

Angle-resolved photoemission is used to determine the temperature-dependent electronic properties of ferromagnetic bulk Gd along Gamma -A of the three-dimensional Brillouin zone. The Delta sub 2 band exchange splitting (0.85 eV) and dispersion (0.5 eV) are in reasonably good agreement with self-consistent local spin-density approximation calculations. The conduction-band magnetic exchange splitting vanishes at the Curie temperature following a conventional power law with a Heisenberg critical exponent. This "Stoner model" collapse of the exchange splitting is in striking contrast to corresponding results observed in transition-metal ferromagnets.