Vinnik Denis A, Tarasova Aleksandra Yu, Zherebtsov Dmitry A, Gudkova Svetlana A, Galimov Damir M, Zhivulin Vladimir E, Trofimov Evgeny A, Nemrava Sandra, Perov Nikolai S, Isaenko Ludmila I, Niewa Rainer
Laboratory of Single Crystal Growth, South Ural State University, Chelyabinsk 454080, Russia.
Institute of Geology and Mineralogy, Siberian Branch Russian Academy of Sciences, Novosibirsk 630090, Russia.
Materials (Basel). 2017 May 25;10(6):578. doi: 10.3390/ma10060578.
Barium hexaferrite powder samples with grains in the μm-range were obtained from solid-state sintering, and crystals with sizes up to 5 mm grown from PbO, Na₂CO₃, and BaB₂O₄ fluxes, respectively. Carbonate and borate fluxes provide the largest and structurally best crystals at significantly lower growth temperatures of 1533 K compared to flux-free synthesis (1623 K). The maximum synthesis temperature can be further reduced by the application of PbO-containing fluxes (down to 1223 K upon use of 80 at % PbO), however, Pb-substituted crystals BaPbFeO with Pb contents in the range of 0.23(2) ≤ ≤ 0.80(2) form, depending on growth temperature and flux PbO content. The degree of Pb-substitution has only a minor influence on unit cell and magnetic parameters, although the values for Curie temperature, saturation magnetization, as well as the coercivity of these samples are significantly reduced in comparison with those from samples obtained from the other fluxes. Due to the lowest level of impurities, the samples from carbonate flux show superior quality compared to materials obtained using other methods.
通过固态烧结获得了晶粒尺寸在微米级的六铁酸钡粉末样品，并分别从氧化铅、碳酸钠和硼酸钡助熔剂中生长出了尺寸达5毫米的晶体。与无助熔剂合成（1623 K）相比，碳酸盐和硼酸盐助熔剂在显著更低的1533 K生长温度下能提供最大且结构最佳的晶体。通过使用含氧化铅的助熔剂，最高合成温度可进一步降低（使用80原子百分比的氧化铅时降至1223 K），然而，会形成铅含量在0.23(2) ≤ ≤ 0.80(2)范围内的铅取代晶体BaPbFeO，这取决于生长温度和助熔剂氧化铅的含量。尽管与从其他助熔剂获得的样品相比，这些样品的居里温度、饱和磁化强度以及矫顽力的值显著降低，但铅取代程度对晶胞和磁参数的影响较小。由于杂质水平最低，碳酸盐助熔剂得到的样品与使用其他方法获得的材料相比质量更优。
