model = sqw_spinw(sw, options) : 3D dispersion(HKL) spin-wave iFunc/sqw_spinw: a 4D S(q,w) with a 3D HKL dispersion obtained from the spinw package from S. Toth. A SpinW object must first be created, and is then converted into an iFunc model for HKL evaluation. The intensity is computed for a neutron scattering experiment. MODEL CREATION: To create the Model, the following syntax should be used: s = sqw_spinw(sq, options); or s = sqw_spinw('CIF_filename', options); with: sq: a spinw object from <a href="https://www.psi.ch/spinw/spinw">SpinW</a>. when omitted, use a square lattice Heisenberg Antiferromagnet with S = 1 and J = 1 options: a set of options to be used for the Model evaluation (structure) options.component: the component to use as intensity, as documented in <a href="matlab:doc sw_egrid">sw_egrid</a> Default is 'Sperp'. Suggested is also 'Sxx+Syy+Szz'. You can get a default model (squareAF) with: s = sqw_spinw('defaults'); MODEL EVALUATION (once created): Once the model is created, you may evaluate it using the standard evaluation call: value = s(p, h,k,l,w) or f=iData(s,p,qh,qk,ql,w); % to get an iData object back with: p: sqw_spinw model parameters (double) p(1)=Gamma energy broadening [meV] p(2)=Temperature of the material [K] p(3)=Amplitude p(4...)= coupling parameters of the Hamiltonian or p='guess' qh: axis along QH in rlu (row,double) qk: axis along QK in rlu (column,double) ql: axis along QL in rlu (page,double) w: axis along energy in meV (double) signal: when values are given, a guess of the parameters is performed (double) output: signal: model value Example: sq = sw_model('squareAF',2,0); % create the SW object s = sqw_spinw(sq); % create the Model qh = linspace(0.01,1.5,30);qk=qh; ql=qh'; w=linspace(0.01,10,50); f = iData(s,s.p,qh,qk,ql,w); plot(log(f(:,:,1,:))); % evaluate and plot Reference: https://en.wikipedia.org/wiki/Phonon SpinW <https://github.com/tsdev/spinw> <https://www.psi.ch/spinw/spinw> S. Toth and B. Lake, J. Phys.: Condens. Matter 27, 166002 (2015). Version: Nov. 26, 2018 See also iData, iFunc/fits, iFunc/plot, gauss, sqw_phonons, sqw_cubic_monoatomic, sqw_vaks, sqw_sine3d <a href="matlab:doc(iFunc,'Models')">iFunc:Models</a> (c) E.Farhi, ILL. License: EUPL.