Spin dynamics in a diluted Heisenberg NN antiferromagnet on a HCP lattice: Zn[sub 1[minus][ital x]]Mn[sub [ital x]]Se (abstract)

Journal Article · Sat May 15 00:00:00 EDT 1993 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.353634· OSTI ID:6667998

Giebultowicz, T M ^[1]; Fernandez-Baca, J A; Nicklow, R M ^[2]; Furdyna, J K; Debska, U ^[3]

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1. University of Notre, Notre Dame, Indiana 46556 (United States) National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
2. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
3. University of Notre Dame, Notre Dame, Indiana 46556 (United States)

The nature of magnetic excitations in disordered and short-range ordered antiferromagnetic systems continues to be an interesting problem. The family of A[sup II][sub 1[minus][ital x]]Mn[sub [ital x]]B[sup VI] alloys (A[sup II]=Zn, Cd, Hg, B[sup VI]=S, Se, Te) offers highly interesting prototypes for such studies. In these systems, which crystallize in the zinc blende (ZB) or wurtzite structure, the Mn ions form, respectively, diluted FCC or HCP Heisenberg spin lattices with dominating nearest-neighbor AF coupling. Due to the strong frustration inherent in such lattices these systems do not exhibit long-range spin order even for Mn concentrations as high as [ital x]=0.70. Neutron scattering studies of spin dynamics in the zinc-blende forms (Zn[sub 1[minus][ital x]]Mn[sub [ital x]]Te and Cd[sub 1[minus][ital x]]Mn[sub [ital x]]Te) have been reported in a recent article.[sup 1] In the present paper we report the results of experiments on a wurtzite-type system, Zn[sub 1[minus][ital x]]Mn[sub [ital x]]Se, with [ital x]=0.55 and 0.40. As in the previous case of ZB alloys, the data reveal the existence of magnon-like modes that are extremely strongly damped, but still show a pronounced dispersive behavior. The range of static AF spin--spin correlations in Zn[sub 1[minus][ital x]]Mn[sub [ital x]]Se is extremely short ([xi]=[kappa][sup [minus]1]=5--15 A), and exhibits a significant anisotropy. The energy of the observed excitation is clearly correlated with [xi], i.e., it is higher in the [ital Q]-space directions for which the correlation range is longer. The results are discussed in the context of the existing theoretical models.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6667998
• Journal Information: Journal of Applied Physics; (United States), Vol. 73:10; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
MANGANESE SELENIDES
MAGNONS
ZINC SELENIDES
ANTIFERROMAGNETIC MATERIALS
DILUTE ALLOYS
HEISENBERG MODEL
INELASTIC SCATTERING
NEUTRONS
ALLOYS
BARYONS
CHALCOGENIDES
CRYSTAL MODELS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETIC MATERIALS
MANGANESE COMPOUNDS
MATERIALS
MATHEMATICAL MODELS
NUCLEONS
QUASI PARTICLES
SCATTERING
SELENIDES
SELENIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
360606* - Other Materials- Physical Properties- (1992-)