The influence of enhanced surface magnetism on finite-size scaling

Abstract

Waldfried, C.; McAvoy, T.; Welipitiya, D.; Dowben, Peter A.; and Vescovo, Elio, "The influence of enhanced surface magnetism on finite-size scaling" (1998). Peter Dowben Publications. 95.

Band structure of strained Gd(0001) films

“…[3][4][5][6] Compression of gadolinium is seen to lead to a suppression of T c , 3,6 while expansion leads to an increase of T c . 7,8 Not only does strain affect the magnetic properties, as now detailed fairly extensively for the perovskites, [9][10][11][12][13][14][15][16][17] but it has long been established that the lattice constant has a profound influence on the electronic structure, 18 -20 even for the thinnest of thin films. [21][22][23][24][25][26] Gd͑0001͒ grown on Mo͑112͒ exhibits a substantial inplane expansive strain compared to a similar thickness of Gd͑0001͒ on W͑110͒.…”

“…27͒ should be applicable to Gd͑0001͒ on Mo͑112͒. 28 While a number of experimental studies have been undertaken to investigate the spin-polarized band structure of strained Gd͑0001͒, 7,8,29 an interpretation of experimental data is complicated by the close proximity of bulk and surface bands, and the large number of observed unoccupied bands, not seen with Gd͑0001͒ on W͑110͒. [30][31][32] A great interest in the behavior of the surface and bulk band structure of gadolinium has provoked a number of theoretical investigations of the Gd͑0001͒ surface using various calculational techniques and approximations for exchange-correlation potential.…”

Strain induced alteration of the gadolinium surface state

“…Two features, the spin majority state at 0.7 eV below E F and the spin minority state at 0.2 eV binding energy are Stonerlike exchange split surface bands. 3 The surface character of these two states has been verified by their sensitivity to small amounts of adsorbates and their two dimensionality of state. Both surface sensitive features do not disperse with changing perpendicular momentum 2 and are therefore confined to the two-dimensional plane at the surface.…”

“…We have been able to obtain strained films of gadolinium, with an increased lattice constant of approximately 4% by growing gadolinium on the corrugated surface of Mo͑112͒. [2][3][4] We investigated the occupied and unoccupied electronic structure of thin films of strained and unstrained Gd͑0001͒. Spin-polarized photoemission experiments were carried out at the new U5UA undulator beamline of the National Synchrotron Light Source ͑NSLS͒ at the Brookhaven National Laboratory in Upton, NY.…”

“…10 In the strained Gd films the bulk spin majority and minority subbands are found at approximately 1.8 eV binding energy at ⌫ , with negligible Stoner-like exchange splitting. 3 There are three features near the Fermi level ͑0 to 1 eV binding energy͒ in the valence band of the strained Gd films. Two features, the spin majority state at 0.7 eV below E F and the spin minority state at 0.2 eV binding energy are Stonerlike exchange split surface bands.…”