Magnetic recording medium containing a substituted hexagonal ferrite
magnetic powder which includes Zr or Hf and which has a temperature
coefficient of coercivity not more than 3.5 oersteds/.degree.C.
    4.
    发明授权
    Magnetic recording medium containing a substituted hexagonal ferrite magnetic powder which includes Zr or Hf and which has a temperature coefficient of coercivity not more than 3.5 oersteds/.degree.C. 失效
    磁性记录介质包含一种替代的六角形铁素体磁粉,其包括ZR或HF,并且具有不超过3.5个/℃的温度系数。

    公开(公告)号:US5077146A

    公开(公告)日:1991-12-31

    申请号:US250576

    申请日:1988-09-29

    IPC分类号: G11B5/706

    CPC分类号: G11B5/70678 Y10S428/90

    摘要: Disclosed is a magnetic powder for high-density magnetic recording, formed of a substituted hexagonal ferrite possessing an average particle diameter in the range of 0.01 to 0.2 .mu.m and a coercivity in the range of 200 to 2,000 Oe and characterized by the fact that the substituted hexagonal ferrite has at least 0.05 to 0.5 atom of at least one element selected from the group consisting of Zr and Hf per chemical formula and at least one element selected from among the elements other than Zr and Hf substituted for part of the Fe atom of the ferrite, and a magnetic recording medium of the present invention comprises a substrate and the magnetic powder mentioned above deposited on the substrate. Since the magnetic powder comprises very minute particles, the magnetic powder and the magnetic recording medium are capable of high-density recording. The magnetic powder has an improved desirably controlled aspect ratio for orientation and the temperature characteristic of coercivity (Hc) as compared with the countertype formed of a hexagonal ferrite which has neither Zr nor Hf substituted for the Fe atom.

    Magnetic powders for magnetic recording media and magnetic recording
media employing said magnetic powder therein
    5.
    发明授权
    Magnetic powders for magnetic recording media and magnetic recording media employing said magnetic powder therein 失效
    用于磁记录介质的磁粉和在其中使用所述磁粉的磁记录介质

    公开(公告)号:US4636433A

    公开(公告)日:1987-01-13

    申请号:US795130

    申请日:1985-11-05

    摘要: A magnetic powder for magnetic recording media comprises a hexagonal crystalline system ferrite containing, as essential components for said hexagonal crystalline system ferrite, iron and oxygen, and at least one of the elements selected from the group of Ba, Sr, Ca and Pb, said iron being substituted by at least one of the elements selected from the group of Ti, Co, Ni, Mn, Cu, Zn, In, Ge, Nb, Zr and Sb; and at least one of Ba, Sr, Ca, Pb being substituted by at least one of the rare earth elements selected from the group of Ce, Pr, Nd, Pm, Sm and Eu. The magnetic powder has a mean particle size of 0.01 to 0.3 .mu.m and a coercive force of 200 and 2000 Oe. The magnetic powder is improved in its saturation magnetization while retaining a suitable coercive force. Accordingly, high reproduction output can be obtained in a magnetic recording medium employing the magnetic powder.

    摘要翻译: 用于磁记录介质的磁性粉末包括六方晶系铁氧体,其包含作为所述六方晶系铁素体,铁和氧以及选自Ba,Sr,Ca和Pb中的至少一种元素的必要组分,所述六方晶系铁氧体包含所述六方晶系铁氧体, 铁被选自Ti,Co,Ni,Mn,Cu,Zn,In,Ge,Nb,Zr和Sb中的至少一种元素取代; 并且Ba,Sr,Ca,Pb中的至少一种被选自Ce,Pr,Nd,Pm,Sm和Eu中的至少一种稀土元素取代。 磁粉的平均粒径为0.01〜0.3μm,矫顽力为200〜2000Oe。 磁性粉末在保持适当的矫顽力的同时提高其饱和磁化强度。 因此,在使用磁性粉末的磁记录介质中可以获得高再现输出。

    Magnetic recording medium
    7.
    发明授权

    公开(公告)号:US5104750A

    公开(公告)日:1992-04-14

    申请号:US501719

    申请日:1990-03-30

    CPC分类号: G11B5/70678 Y10S428/90

    摘要: In the magnetic recording medium according to the present invention comprising a magnetic recording medium layer where a magnetic paint containing Ba ferrite magnetic powder is coated on the substrate, Hc in the oriented direction ranging from 900 to 1500 Oe, the squareness in the oriented direction being 0.80 or more, and the ratio Hr(90.degree.)/Hr(0.degree.) of the remanence coercive force Hr(0.degree.) in the oriented direction (0.degree.) and the remanence coercive force Hr (90.degree.) in the direction (90.degree.) perpendicular to the oriented direction ranging from 1

    Barium ferrite magnetic powder and recording medium employing the same
    8.
    发明授权
    Barium ferrite magnetic powder and recording medium employing the same 失效
    钡铁氧体磁粉及采用其的记录介质

    公开(公告)号:US4582623A

    公开(公告)日:1986-04-15

    申请号:US646165

    申请日:1984-08-31

    CPC分类号: G11B5/70678

    摘要: Disclosed is a barium ferrite magnetic powder comprising particles characterized by (A) a mean particle size of 0.3 .mu.m or smaller and (B) the presence of Sr, Ca and Si in respective amounts of 0.2 wt. % or less as SrO, 0.15 wt. % or less as CaO, and 0.3 wt. % or less as SiO.sub.2. Also disclosed is a recording medium comprising the barium ferrite magnetic powder.

    摘要翻译: 公开了一种钡铁氧体磁粉,其特征在于,(A)平均粒径为0.3μm以下,(B)Sr,Ca,Si的存在量分别为0.2重量% %以下,SrO 0.15% %以下,CaO为0.3重量%以下。 %以下。 还公开了包含钡铁氧体磁性粉末的记录介质。