公开(公告)号：DE2344644A1

公开(公告)日：1974-05-02

申请号：DE2344644

申请日：1973-09-05

Applicant: BASF AG

Inventor： KOESTER EBERHARD DR ,  WUNSCH GERD DR ,  DEIGNER PAUL DR ,  GRAW DIETER DR ,  KNELLER ECKART PROF DR

IPC: C09D5/23 ,  C09D7/12 ,  G03G5/16 ,  G11B5/02 ,  G11B5/62 ,  G11B5/64 ,  G11B5/70 ,  G11B5/706 ,  G11B23/28

Abstract: The invention relates to a method of recording magnetic signals on magnetic recording media containing an exchange-anisoptropic material at a temperature lower than, equal to or higher than the Neel temperature of this magnetic material. After the recording has been made, the magnetic recording medium is heated to a temperature equal to, or higher than, the Neel temperature, then cooled down to a temperature below the Neel temperature and the recording temperature, following which it is provided with an indicator which betrays re-heating.

公开(公告)号：DE4141763A1

公开(公告)日：1993-06-24

申请号：DE4141763

申请日：1991-12-18

Applicant: BASF AG

Inventor： RICHTER HANS JUERGEN DR ,  SCHWAB EKKEHARD DR ,  JAKUSCH HELMUT DR ,  HIBST HARTMUT DR ,  GRAU WERNER DR ,  KNELLER ECKART PROF DR ,  HAWIG REINHARD

IPC: G11B5/706 ,  H01F1/03 ,  H01F1/057 ,  H01Q17/00 ,  H02K1/02

Abstract: A magnetisable material consists of at least two ferro- and/or ferrimagnetic phases which are magnetically coupled to each other by magnetic exchange coupling. At least one of the phases is a hard magnetic phase and at least one of the phases is a soft magnetic phase. The vol. percentage of the soft magnetic phase is at least 30%. At least 65% of the original saturation remanence is obtd. again after prior magnetic saturation in a direction corresp. to the application of an opposite magnetic field which is the same as the coercive field strength of the magnetic material, and after removing the field. The saturation remanence is at least 50% of the saturation magnetisation. The material is mfd. by spraying a melt of rare earth metals, Fe, B, a transition metal and Si on to a rotating metal roll in an inert atmos., and annealing the flakes produced at 670-780 deg.C to give the desired ratio of hard- to soft magnetic phases. Pref. an alloy of compsn. RExFeyBzSiuTv is used as the magnetic material, where RE is one or more rare earth metals and/or Y, Zr and Hf, and T is one or more transition metal with a body-centred cubic structure, and where x is not greater than 10 atom %, y is not greater than 85 atom %, z is not greater than 25 atom %, u is not greater than 10 atom %, and v is not greater than 10 atom %. Up to 10 atom % Fe may be replaced by Ni and/or Co. The soft magnetic phases comprises alpha-Fe and Fe3B, and the hard magnetic phase comprises Nd2Fe14B.