EFFECTIVE EXCHANGE INTEGRAL (J1 + J2) IN EuS FROM STANDING SPIN WAVE RESONANCE
نویسندگان
چکیده
The standing spin wave resonance has been measured in thin films of EuS at 1.1 OK in the perpendiculai configuration. The magnon dispersion relation is found to be quadratic in the observed region of k (k < 0.2 xla). The effective exchange energy (JI $. Jz) determined is 0.088 f 0.010 OK. This value is lower than that calculated by Passenheim et al. [7] from specific heat measurements. This discrepancy is attributed to correlation effects, analogous to those calculated by Silberglitt et a1 [8] for CrBr3. The excitation spectrum of a Heisenberg ferromagnet can be derived from its Hamiltonian : where p is the Bohr magneton and 2 Jij is the exchange interaction between the spins Si and Sj at the lattice sites i and j. By applying the HolsteinPrimakoff transformation to (1) and restricting Jij to nearest and next nearest neighbors (Jl and J, resp.) the single particle dispersion relation for magnons (spin waves) is calculated : hwk = gPH + 2 SJ1 [l exp(ikll)]
منابع مشابه
اثر برهم‌کنش‌های چهار اسپینی برروی سیمای فاز مدل هایزنبرگ J1-J2 پادفرومغناطیس اسپین 3/2 شبکه لانه زنبوری
In this study, the effect of four-spin exchanges between the nearest and next nearest neighbor spins of honeycomb lattice on the phase diagram of S=3/2 antiferomagnetic Heisenberg model is considered with two-spin exchanges between the nearest and next nearest neighbor spins. Firstly, the method is investigated with classical phase diagram. In classical phase diagram, in addition to Neel order,...
متن کاملنظمهای مغناطیسی مدل هایزنبرگ j1-j2 پادفرومغناطیس شبکه‌ی لانه زنبوری در حضور برهم‌کنش ژیالوشینسکی-موریا
Motivated by recent experiments that detects Dzyaloshinskii-Moriya (DM) interaction in , we study the effects of DM interaction on magnetic orders of J1-J2 antiferromagnetic Heisenberg model. First, we find the classical phase diagram of the model using Luttinger-Tisza approximation. In this approximation, the classical phase diagram has two phases. For , the model has canted Neel and DM intera...
متن کاملVariational study of J1- J2 Heisenberg model on kagome lattice using projected Schwinger-boson wave functions
Motivated by the unabating interest in the spin-1/2 Heisenberg antiferromagnetic model on the kagome lattice, we investigate the energetics of projected Schwinger-boson (SB) wave functions in the J1-J2 model with antiferromagnetic J2 coupling. Our variational Monte Carlo results show that Sachdev’s Q1 = Q2 SB ansatz has a lower energy than the Dirac spin liquid for J2 0.08J1 and the q = 0 Jastr...
متن کاملMonte Carlo studies of critical phenomena in mixed spin-3/2 and spin-5/2 Ising model on square lattice
We used a Monte Carlo simulation to analize the magnetic behavior of Ising model of mixed spins S i = ±3/2,±1/2 and σ j = ±5/2,±3/2,±1/2, on a square lattice. Were studied the possible critical phenomena that may emerge in the region around the multiphase point (D/|J1| = −3, J2/|J1| = 1) and the dependence of the phase diagrams with the intensities of the anisotropy field of single ion (D/|J1|)...
متن کاملPlaquette ordered phase and quantum spin liquid in the spin- 2 J1-J2 square Heisenberg model
We study the spin1 2 Heisenberg model on the square lattice with firstand second-neighbor antiferromagnetic interactions J1 and J2, which possesses a nonmagnetic region that has been debated for many years and might realize the interesting Z2 spin liquid (SL). We use the density matrix renormalization group approach with explicit implementation of SU(2) spin rotation symmetry and study the mode...
متن کامل