There is some confusion here about types of paramagnetism.
If the spin-polarised and non-spin polarised results are the same, it merely means that the spin up and spin down bands are at equal energies. Pt has no unpaired spins so no magnetic moment. It could from the calculation be diamagnetic or Pauli paramagnetic. As it is a metallic conductor, the latter is likely, so the non-magnetic form is the Pauli paramagnetic ground state. The spin up and spin down bands will acquire different energies if you apply a magnetic field. The original query was concerned with Gd which has unpaired f electron spins and it is this type of system that becomes paramagnetic as you raise the temperature. NiS which was also mentioned I assume contains Ni 2+ ions. In square planar environments these have no unpaired spins and so no magnetic moment and the compounds will be diamagnetic. In tetrahedral environments the ion has unpaired spins and so a magnetic moment. The change to no magnetic moment coincided with a first iorder phase transition so it is most likely linked to a change in structure and hence the local environment of Ni. Elaine A. Moore The Open University, UK ________________________________ From: Wien <wien-boun...@zeus.theochem.tuwien.ac.at> on behalf of Fecher, Gerhard <fec...@uni-mainz.de> Sent: 28 November 2016 07:33 To: A Mailing list for WIEN2k users Subject: Re: [Wien] Discrepancy in the simulation of the paramagnetic state I hope you agree that Pt is paramagnetic I did two calculations for Pt, one was spin polarized the other not. The results are identical, no resulting magnetic moment (indeed, I started with one in the spin polarized case), did I play a trick or did Wien2k play a trick ? but may be Wien2k can not be used to calculate the electronic structure of Pt, because it is paramagnetic (Pt, not Wien2k !). I hope you agree that Pt is paramagnetic even at Zero temperature. why do I need to include temperature effects to calculate the ground state of Pt (at 0 K, where else) ? ... and what should MtC calculations tell me about it ? Remark 1: Calculations may be "spin polarized" (LSDA) or not (LDA) or they may be even more sophisticated "non-colinear spin polarized" or they may be for "disordred local moments" or for "spin spirals", or ???, just to name some. Remark 2: Materials may be diamagnetic, paramagnetic (Langevin, Pauli, van Vleck), ferromagnetic (localised moments, itinerant), ferrimagnetic (collinear, non-collinear), etc.. Therefore, I repeat my question: How do you distinguish diamagnetic, paramagnetic, ferromagnetic, and ... states ? The answer is for you, not for me. I tried to calculate for Pt using Hohenberg Kohn DFT, but I could not find the functional, all I found was some approximation using wave functions. Don't worry I will not ask a question about it ;-) Ciao Gerhard DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: "I think the problem, to be quite honest with you, is that you have never actually known what the question is." ==================================== Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz and Max Planck Institute for Chemical Physics of Solids 01187 Dresden ________________________________________ Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Xavier Rocquefelte [xavier.rocquefe...@univ-rennes1.fr] Gesendet: Sonntag, 27. November 2016 12:46 An: wien@zeus.theochem.tuwien.ac.at Betreff: Re: [Wien] Discrepancy in the simulation of the paramagnetic state Just to add one more point to this funny discussion, the term "paramagnetic" is sometimes used in the DFT litterature in an improper way. It could clearly lead to misunderstanding for researchers who do not know so much on how magnetic properties could evolve with temperature and applied magnetic field. When you see in a paper "paramagnetic state" simulated using DFT ... it is NOT paramagnetic at all, it is simply a trick which must be considered with care as previously mentionned by Peter, Eliane and Martin. If you want to simulate a paramagnetic state you need to include the temperature effects, i.e. you should consider the spin dynamics and the competition between magnetic exchange interactions and thermal fluctuations. This could be done, at least, using Monte-Carlo calculations based on an effective hamiltonian constructed on top of DFT parameters (including magnetic exchange and anisotropy at least). Best Regards Xavier Le 27/11/2016 à 10:01, Fecher, Gerhard a écrit : > How do you distinguish a diamagnetic, a paramagnetic, a ferromagnetic, and an > antiferromagnetic state. > > Think ! > > This will answer your question, hopefully. > > Ciao > Gerhard > > DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: > "I think the problem, to be quite honest with you, > is that you have never actually known what the question is." > > ==================================== > Dr. Gerhard H. Fecher > Institut of Inorganic and Analytical Chemistry > Johannes Gutenberg - University > 55099 Mainz > and > Max Planck Institute for Chemical Physics of Solids > 01187 Dresden > ________________________________________ > Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von > Abderrahmane Reggad [jazai...@gmail.com] > Gesendet: Samstag, 26. November 2016 22:30 > An: wien@zeus.theochem.tuwien.ac.at > Betreff: Re: [Wien] Discrepancy in the simulation of the paramagnetic state > > Thank you Prof Blaha for your quick answer. > > The Ni atom is 3d transition metal . But my question is about the simulation > of the paramagnetic state. There are many people that considere that the > paramagnetic state is the non-spin polarierd one and the magnetic moment is > zero, but you say no and the magnetic moments exist in arbitrary directions > and my quoting is about that. > > I have given 2 examples for that discrepancy with your statement. > > Best regards > -- > Mr: A.Reggad > Laboratoire de Génie Physique > Université Ibn Khaldoun - Tiaret > Algerie > > > _______________________________________________ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien Wien -- A Mailing list for WIEN2k users<http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien> zeus.theochem.tuwien.ac.at A Mailing list for WIEN2k users. Please post questions, suggestions or comments about WIEN2k ONLY in this list. 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