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Iida, Kazuki*; Yoshida, Hiroyuki*; Nakao, Akiko*; Jeschke, H. O.*; Iqbal, Y.*; Nakajima, Kenji; Kawamura, Seiko; Munakata, Koji*; Inamura, Yasuhiro; Murai, Naoki; et al.
Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06
Times Cited Count:22 Percentile:80.38(Materials Science, Multidisciplinary)Crystal and magnetic structures of the mineral centennialite CaCu(OD)Cl 0.6DO are investigated by means of synchrotron X-ray diffraction and neutron diffraction measurements complemented by density functional theory (DFT) and pseudofermion functional renormalization group (PFFRG) calculations. In CaCu(OD)Cl 0.6DO, Cu ions form a geometrically perfect kagome network with antiferromagnetic . No intersite disorder between Cu and Ca ions is detected. CaCu(OD)Cl 0.6DO enters a magnetic long-range ordered state below = 7.2 K, and the =0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)B. Our DFT calculations indicate the presence of antiferromagnetic and ferromagnetic superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin- PFFRG analysis shows a dominance of =0 type magnetic correlations, consistent with and indicating proximity to the observed =0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a -- kagome antiferromagnet.
Takeda, Masayasu; Kakurai, Kazuhisa; Sunaga, Kazuyuki*; Tsunoda, Masakiyo*; Takahashi, Migaku*
no journal, ,
A giant magnetic moment which was larger than the saturation magnetization of pure Iron was reported in FeN thin films, but a reliable value of the giant moment has not been experimentally fixed yet. In addition, the origin is still an open question although several models has been proposed. One of them is that phase of FeN in which N atoms are ordered in the bct structure is the origin of the giant magnetic moment. It is, however, not supported by the band calculation of this compound. In this talk, polarized neutron diffraction experiments will be reported to determine the accurate magnitude of the saturated magnetic moment of this film.
Takeda, Masayasu; Kakurai, Kazuhisa; Sunaga, Kazuyuki*; Tsunoda, Masakiyo*; Takahashi, Migaku*
no journal, ,
There is still an issue of existence of the giant magnetic moments in FeN thin films because the scattered values of the magnitude of the Fe moments have been reported. The origin is also still an open question although several theoretical models which suggested the giant magnetic moments came from the " phase of FeN have been proposed. We have performed the polarized neutron diffraction measurements of the FeN thin films using the polarized neutron triple-axis spectrometer, TAS-1, installed at JRR-3. Similar values of the magnitude of the Fe magnetic moments to the -Fe (pure iron) were obtained by the measurements.
Takeda, Masayasu; Kakurai, Kazuhisa; Sunaga, Kazuyuki*; Tsunoda, Masakiyo*; Takahashi, Migaku*
no journal, ,
"-FeN is a promising candidate for the recording media of high-density magnetic recoding tapes because it was reported that this compound has a giant magnetic moment of 2.9 T larger than pure Fe. It was, however, difficult to synthesize a homogeneous specimen of a single phase. We have succeeded to synthesize the homogeneous and single-phase FeN thin films, and have been investigated the giant magnetic moments using Mssbauer spectroscopy and polarized neutron diffractometry. In this talk, the results of the polarized neutron diffraction measurements are reported.
Takeda, Masayasu; Kakurai, Kazuhisa; Sunaga, Kazuyuki*; Tsunoda, Masakiyo*; Takahashi, Migaku*
no journal, ,
FeN nano particles are believed to be promising magnetic recording media for tape of next generations. In this ferromagnet, the giant magnetic moments up to 2.9 T are reported in thin films of FeN. However, it has been difficult to synthesize FeN films which showed reproducible experimental results. Recently a new NH nitrification method was developed, and quantitative analysis of the experimental results such as magnetization measurement and Mssbauer spectroscopy can be done with the samples. In this talk we report a recent results of polarized neutron powder diffraction measurements of the FeN thin films to know whether the giant magnetic moments exists in the films or not.
Takeda, Masayasu; Kakurai, Kazuhisa; Tsunoda, Masakiyo*; Takahashi, Migaku*
no journal, ,
no abstracts in English