The derivation of effective spin Hamiltonians and the origin of the magnetic field induced transition in orthormbic La sub 2 CuO sub 4
La{sub 2}CuO{sub 4} undergoes a magnetic field induced transition in a field of {approx}5.7 Tesla at low temperatures. The origin of this transition is the Dzyaloshinskii-Moriya interaction which is present in effective spin Hamiltonians for systems of sufficiently low symmetry, and, which leads to weak ferromagnetism in the CuO planes in La{sub 2}CuO{sub 4}. It is shown here how this interaction depends on symmetry and how its form changes with structural phase transitions which occur in compounds closely related to La{sub 2}CuO{sub 4}. These different forms of the interaction lead to different properties in magnetic fields. I also discuss how the approach presented here of determining an effective spin Hamiltonian from symmetry is related to the determination of terms in the free expansion close to a second order phase transition. It is pointed out that the present approach may be extended to itinerant systems and 1 take UPt{sub 3} as an example. 28 refs., 4 figs.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5645396
- Report Number(s):
- LA-UR-91-1680; CONF-9105151-5; ON: DE91013743
- Resource Relation:
- Conference: Physical phenomena at high magnetic fields, Tallahassee, FL (USA), 15-18 May 1991
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigation of a Hamiltonian with two sources of anisotropy: The Dzyaloshinskii--Moriya and single-site interactions
Calculation of the static magnetization of metamagnetic La sub 2 CuO sub 4
Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER OXIDES
SPIN ORIENTATION
LANTHANUM OXIDES
ANISOTROPY
FERROMAGNETISM
HAMILTONIANS
MAGNETIC FIELDS
SPIN FLIP
CHALCOGENIDES
COPPER COMPOUNDS
LANTHANUM COMPOUNDS
MAGNETISM
MATHEMATICAL OPERATORS
ORIENTATION
OXIDES
OXYGEN COMPOUNDS
QUANTUM OPERATORS
RARE EARTH COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties
656100 - Condensed Matter Physics- Superconductivity