Microscopic Aspects of Magnetic Lattice Demagnetizing Factors

Abstract

The demagnetizing factor N is of both conceptual interest and practical importance. Considering localized magnetic moments on a lattice, we show that for non-ellipsoidal samples, N depends on the spin dimensionality (Ising, XY, or Heisenberg) and orientation, as well as the sample shape and susceptibility. The generality of this result is demonstrated by means of a recursive analytic calculation as well as detailed Monte Carlo simulations of realistic model spin Hamiltonians. As an important check and application, we also make an accurate experimental determination of N for a representative collective paramagnet (i.e. the Dy2Ti2O7 spin ice compound) and show that the temperature dependence of the experimentally determined N agrees closely with our theoretical calculations. Our conclusion is that the well established practice of approximating the true sample shape with "corresponding ellipsoids" for systems with long-range interactions will in many cases overlook important effects stemming from the microscopic aspects of the system under consideration.

8 pages, 5 figures

References in corpus (4)

• Statistical mechanics and dynamics of solvable models with long-range interactions
• Dy2Ti2O7 Spin Ice: a Test Case for Emergent Clusters in a Frustrated Magnet
• Pinch Points and Kasteleyn Transitions: How Spin Ice Changes its Entropy
• Neutron Larmor diffraction investigation of the rare earth pyrochlores $R_2$Ti${}_2$O${}_7$ ($R$ = Tb, Dy, Ho)

Cited by in corpus (10)

• Special temperatures in frustrated ferromagnets
• Emergence of mesoscale quantum phase transitions in a ferromagnet
• Dipolar Spin Ice Under Uniaxial Pressure
• LiHoF${}_4$: Cuboidal Demagnetizing Factor in an Ising Ferromagnet
• Effects of uniaxial pressure on the spin ice Ho2Ti2O7
• Screening and the Pinch Point Paradox in Spin Ice
• Tunable critical correlations in kagome ice
• Power spectrum of magnetic relaxation in spin ice: anomalous diffusion in a Coulomb fluid
• Magnetic monopole relaxation effects in spin ice Dy${}_2$Ti${}_2$O${}_7$
• Magnetostatic modes and criticality in quantum-Ising materials