000281650 001__ 281650
000281650 005__ 20210129221812.0
000281650 037__ $$aFZJ-2016-01338
000281650 041__ $$aEnglish
000281650 1001_ $$0P:(DE-Juel1)164129$$aSchmitz, D.$$b0$$ufzj
000281650 1112_ $$aXAFS16 satellite meeting “Application of XAFS to the study of magnetic Materials”$$cStuttgart$$d2015-08-30 - 2015-09-02$$wGermany
000281650 245__ $$aHuge intra-atomic dipole moment of the iron spin-density in the low temperature phase of magnetite
000281650 260__ $$c2015
000281650 3367_ $$0PUB:(DE-HGF)24$$2PUB:(DE-HGF)$$aPoster$$bposter$$mposter$$s1454315593_19488
000281650 3367_ $$033$$2EndNote$$aConference Paper
000281650 3367_ $$2DataCite$$aOutput Types/Conference Poster
000281650 3367_ $$2DRIVER$$aconferenceObject
000281650 3367_ $$2ORCID$$aCONFERENCE_POSTER
000281650 3367_ $$2BibTeX$$aINPROCEEDINGS
000281650 520__ $$aMagnetite nanoparticles (NPs) with 6 nm diameter and a 200 nm thick magnetite reference film were studied with a combination of experimental and theoretical methods, i.e. x-ray absorption near edge spectroscopy (XANES), x-ray magnetic circular dichroism (XMCD), vibrating sample magnetometry (VSM) and electronic structure calculations based on density functional theory. For the NPs, increases of the white line intensity and the XMCD signal with increasing temperature were observed between 50 K and 100 K (Fig. 1a, b). A similar increase of the XMCD signal was also observed for the film between 125 K and 175 K, which is above its Verwey transition temperature of 120 K in agreement with the unusual temperature dependence of the magneto-crystalline anisotropy. A sum rule analysis of the XMCD spectra revealed that the transitions observed with XMCD are due to changing effective Fe spin moments. Since the transitions were not observed with VSM, we attribute them to changes of the intra-atomic dipole moment of the Fe 3d spin-density distribution, i.e. the Tz term in the XMCD sum rule for the effective spin moment. This conclusion was verified and explained theoretically. The sizable negative intra-atomic dipole moment in the monoclinic low-temperature phase of magnetite is due to the contribution of Fe2+ ions on B4 sites (-1.44 μB per atom) which is partly compensated by Fe2+ ions on B1 sites (0.72 μB per atom). It is a local indicator for the Verwey transition in small magnetite nanoparticles which is usually screened by blocking effects in classical magnetometry.
000281650 536__ $$0G:(DE-HGF)POF3-522$$a522 - Controlling Spin-Based Phenomena (POF3-522)$$cPOF3-522$$fPOF III$$x0
000281650 7001_ $$0P:(DE-Juel1)162347$$aSchmitz-Antoniak, C.$$b1$$ufzj
000281650 7001_ $$0P:(DE-HGF)0$$aWarland, A.$$b2
000281650 7001_ $$0P:(DE-HGF)0$$aDarbandi, M.$$b3
000281650 7001_ $$0P:(DE-HGF)0$$aHaldar, S.$$b4
000281650 7001_ $$0P:(DE-HGF)0$$aBhandary, S.$$b5
000281650 7001_ $$0P:(DE-HGF)0$$aEriksson, O.$$b6
000281650 7001_ $$0P:(DE-HGF)0$$aSanyal, B.$$b7
000281650 7001_ $$0P:(DE-HGF)0$$aWende, H.$$b8
000281650 909CO $$ooai:juser.fz-juelich.de:281650$$pVDB
000281650 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)164129$$aForschungszentrum Jülich GmbH$$b0$$kFZJ
000281650 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)162347$$aForschungszentrum Jülich GmbH$$b1$$kFZJ
000281650 9131_ $$0G:(DE-HGF)POF3-522$$1G:(DE-HGF)POF3-520$$2G:(DE-HGF)POF3-500$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bKey Technologies$$lFuture Information Technology - Fundamentals, Novel Concepts and Energy Efficiency (FIT)$$vControlling Spin-Based Phenomena$$x0
000281650 9141_ $$y2015
000281650 915__ $$0StatID:(DE-HGF)0550$$2StatID$$aNo Authors Fulltext
000281650 9201_ $$0I:(DE-Juel1)PGI-6-20110106$$kPGI-6$$lElektronische Eigenschaften$$x0
000281650 980__ $$aposter
000281650 980__ $$aVDB
000281650 980__ $$aUNRESTRICTED
000281650 980__ $$aI:(DE-Juel1)PGI-6-20110106