Magnetic interactions in high-energy ball-milled <textbox>NiZnFe₂O₄/SiO₂textbox> composites

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• 作者：G. Pozo L&#xf3 ; pez ; S.P. Silvetti ; S.E. Urreta ; E.D. Cabanillas
• 关键词：NiZn ferrite/tyle="text-decoration ; none ; color ; black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml36&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=2f26cba4a79bf9d241a6c5f30a0
• 刊名：Physica B
• 出版年：2007
• 期刊代码：53_09214526
• 类别：ph
• 出版时间：1 September 2007
• 卷：398
• 期：2
• 页码：241-244
• 文件大小：351 K

摘要

Composites tyle="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml29&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=ebc50923b97dcf39186336a5b1e83593" title="Click to view the MathML source">Ni_0.5Zn_0.5Fe₂O₄/SiO₂ are obtained after high-energy ball milling precursor oxides, in stoichiometric proportions, for 200 h at room temperature and further isothermal annealing for 1 h at 1273 K, under air and argon atmosphere, respectively. After 200 h grinding, a complex microstructure develops with small hematite crystals mixed with tyle="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml30&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=9b55288bdad514dc23d1f4d5efd29468" title="Click to view the MathML source">SiO₂ and remanent NiO and ZnO particles, and very small NiZn ferrite clusters, reaching a mean size of thURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml31&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=d323b47811c9a1321f6b35b5fac8144c">ttp://www.sciencedirect.com/cache/MiamiImageURL/B6TVH-4NJ20G0-5-18/0?wchp=dGLbVlb-zSkWb" alt="Click to view the MathML source" align="absbottom" border="0" height=13 width=46>. The high temperature treatments remove the hematite grains from the powder and promote the growth of NiZn ferrite grains to reach mean sizes nearly thURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml32&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=ee3fc6dadd8ec0decb19b4ee073ac75e">ttp://www.sciencedirect.com/cache/MiamiImageURL/B6TVH-4NJ20G0-5-19/0?wchp=dGLbVlb-zSkWb" alt="Click to view the MathML source" align="absbottom" border="0" height=13 width=54>. For treatments in oxidizing atmospheres, the major phases are tyle="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml33&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=999dfd41581cbcb4717ea29bbcde455d" title="Click to view the MathML source">SiO₂ and NiZn ferrite, while for annealing in Ar a new phase appears, fayalite, which is paramagnetic at room temperature. The tyle="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml34&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=a8a811ae24e905ee20283b5770cdd505" title="Click to view the MathML source">M–tyle="text-decoration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TVH-4NJ20G0-5&_mathId=mml35&_user=10&_cdi=5535&_rdoc=21&_acct=C000050221&_version=1&_userid=10&md5=758aa60b0eb8edfd36f90334aee3bf71" title="Click to view the MathML source">H loops are all well described by the sum of a ferromagnetic and a superparamagnetic-like contribution. The observed properties are interpreted considering the different magnetic phases obtained, their crystal sizes and their mutual interactions.