Defect driven magnetism in calcium hexaboride

Lofland, S. E.; Seaman, Brian; Ramanujachary, Kandalam V.; Hur, N.; Cheong, Sang‐Wook

doi:10.1103/physrevb.67.020410

Cited by 37 publications

(28 citation statements)

References 12 publications

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“…7,8 Nonetheless, there are persistent indications of small ferromagnetic moments in CaB 6 , which depend on sample stoichiometry and heat treatment. 4,6,9 We recently observed large moments in disordered thin films of CaB 6 and SrB 6 . 10 Other reports of what may be called "d 0 ferromagnetism" are for certain carbon polymorphs which may contain a high concentration of defects.…”

Section: Introductionmentioning

confidence: 99%

Magnetism in hafnium dioxide

et al. 2005

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Thin films of HfO 2 produced by pulsed-laser deposition on sapphire, yttria-stabilized zirconia, or silicon substrates show ferromagnetic magnetization curves with little hysteresis and extrapolated Curie temperatures far in excess of 400 K. The moment does not scale with film thickness, but in terms of substrate area it is typically in the range 150-400 B nm −2 . The magnetization exhibits a remarkable anisotropy, which depends on texture and substrate orientation. Pure HfO 2 powder develops a weak magnetic moment on heating in vacuum, which is eliminated on annealing in oxygen. Lattice defects are the likely source of the magnetism.

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Section: Introductionmentioning

confidence: 99%

Magnetism in hafnium dioxide

et al. 2005

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“…Experimental evidence exists that magnetization is enhanced and the ordering temperature progressively increases during the sample storage in air. If ferromagnetism were due to the Fe contribution, the formation of Fe oxides in air would lead to opposite results: iron oxides have lower values of both magnetization and Curie temperature [28].…”

Section: Article In Pressmentioning

confidence: 98%

“…However, it is difficult to apply the model of the induced magnetism to polymerized fullerenes, at least quantitatively. The spin decay length in graphite is estimated as tens of nanometers [28], while ferromagnetic domains in fullerenes are observed at impurity-free half-millimeter areas. Also, it is difficult to assume that the moment is induced by the impurities with Fe concentration less than 1 ppm (B1 mg/g).…”

Section: Article In Pressmentioning

confidence: 99%

Magnetism in polymerized fullerenes

Makarova

2004

Journal of Magnetism and Magnetic Materials

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“…To explore the unexpected ferromagnetism reported in the slightly doped alkaline-earth metal hexaborides, particularly in CaB 6 , considerable experiments and theory calculation had been done for many years [1][2][3][4]. Currently one possible interpretation of the magnetic mechanism is that it maybe originated from intrinsic defects.…”

Section: Introductionmentioning

confidence: 99%

Tuning The Crystallographic Structure And Morphology Of Nanocrystalline CaB6 Films Deposited By DC Magnetron Sputtering

Zhang

Zhao

Liu

et al. 2015

Archives of Metallurgy and Materials

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Through changing the argon pressure, CaB 6 films with different crystallographic orientation and morphology on glass substrates were prepared by direct current (DC) magnetron sputtering method. The film textures, crystallite sizes, composition and morphology were investigated by a spectrum of characterizing techniques in terms of X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectrometer (FESEM-EDS), atomic force microscopy (AFM), Raman shift spectroscopy. The influence of argon pressure on microstructure was studied. The average grain size increased with the argon pressure increasing from 0.8 Pa to 1.5 Pa. Meanwhile, the dominant crystal face changed from (110) to (100). Then the grain size decreased when the argon pressure increased to 2.0 Pa. The surface morphology evolved from typical cauliflower-like nanocrystalline clusters to faceted rectangular pyramids. It was found that considerable amount of argon atoms were trapped in the films. The formation process of CaB 6 films was also analyzed in this paper.Keywords: CaB 6 films, crystallographic structure, morphology, argon pressure Warstwy CaB 6 naniesiono na podłoża szkliste metodą magnetronowego rozpylania stałoprądowego (DC). Poprzez kontrolę ciśnienia argonu otrzymano warstwy o różnej morfologii i orientacji krystalograficznej. Strukturę, wielkość krystalitów oraz skład chemiczny warstw badano przy zastosowaniu następujących technik: dyfrakcji rentgenowskiej (XRD), skaningowej mikroskopii elektronowej w połączeniu ze spektroskopią dyspersji energii promieniowania rentgenowskiego (SEM-EDS), mikroskopii sił atomowych (AFM) oraz spektroskopii Ramana. Badano wpływ ciśnienia argonu na mikrostrukturę warstwy. Wraz ze wzrostem ciśnienia argonu z 0,8 Pa do 1,5 Pa zwiększyła się średnia wielkość ziaren przy jednoczesnej zmianie głównych kierunków krystalograficznych -z (110) w (100). Natomiast w wyniku dalszego wzrostu ciśnienia do 2,0 Pa, wielkość ziaren zmniejszyła się. Zaobserwowano także zmiany w morfologii powierzchni. Stwierdzono, że znaczna ilość atomów argonu została uwięziona w warstwach. W niniejszej pracy poddano także analizie proces powstawania warstw CaB 6 .

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Defect driven magnetism in calcium hexaboride

Cited by 37 publications

References 12 publications

Magnetism in hafnium dioxide

Magnetism in hafnium dioxide

Magnetism in polymerized fullerenes

Tuning The Crystallographic Structure And Morphology Of Nanocrystalline CaB6 Films Deposited By DC Magnetron Sputtering

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