IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Wednesday Sessions
       Session EL+MI-WeM

Paper EL+MI-WeM10
Epitaxial Growth of an n-Type Ferromagnetic Semiconductor: CdCr@sub 2@Se@sub 4@@footnote *@

Wednesday, October 31, 2001, 11:20 am, Room 111

Session: Spintronics III: Ferromagnetic Semiconductors
Presenter: Y.D. Park, Naval Research Laboratory
Authors: Y.D. Park, Naval Research Laboratory
A.T. Hanbicki, Naval Research Laboratory
J.E. Mattson, Naval Research Laboratory
B.T. Jonker, Naval Research Laboratory
Correspondent: Click to Email
Ferromagnetic semiconductors (FMSs) provide unprecedented opportunity to tune and optimize spin-dependent behavior in semiconductor device heterostructures. Most efforts have focused on III-Mn-V materials such as GaMnAs, which are p-type only.@footnote 1@ Since efficient spin injection and very long spin scattering lengths have been confirmed for electrons rather than holes in semiconductors such as GaAs,@footnote 2-4@ one would like to realize FMS materials which are both n-type and can be epitaxially grown on a readily available device-quality substrate. We report here the epitaxial growth of FMS CdCr@sub 2@Se@sub 4@(001) films on both GaAs and GaP(001) substrates, and describe the structural, magnetic and electronic properties. The samples were grown by molecular beam epitaxy from elemental K-cell sources, and exhibit a 1x1 RHEED pattern during growth. The film structure, orientation and composition were determined by post-growth x-ray diffraction and fluorescence measurements. SQUID magnetometry data confirm ferromagnetic order with a Curie temperature of 130 K, as in the bulk material, and hysteretic behavior with significant remanence. The easy axis is in-plane with a coercive field of ~125 Oe. Temperature dependent transport data show that the films are semiconducting in character, and lightly n-type as grown. We further describe efforts at controlled doping and electrical spin injection from CdCr@sub 2@Se@sub 4@ contacts into GaAs-based LED heterostructures. @FootnoteText@ @footnote *@ This work was supported by the DARPA SpinS program and ONR. @footnote 1@ Ohno, Science 281, 951 (1998). @footnote 2@ Fiederling et al, Nature 402, 787 (1999). @footnote 3@ Jonker et al, PRB 62, 8180 (2000); Park el al, APL 77, 3989 (2000). @footnote 4@ Oestreich et al, APL 74, 1251 (1999).