Magnetic properties of ultrathin films studied by circular dichroism in X-ray spectroscopies
Magnetic properties of ultrathin films studied by circular dichroism in X-ray spectroscopies
The magnetic properties of Mn overlayers in the submonolayer range on the ferromagnetic substrates Fe(100) and Ni(100) and of fee-Fe overlayers on Cu(100) andCo(100) have been investigated by means of magnetic circular dichroism in x-ray absorption spectroscopy (MCXD). Additionally, spin and angular...
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Personal Name(s): | Schmitz, D. (Corresponding author) |
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Contributing Institute: |
Publikationen vor 2000; PRE-2000; Retrocat |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
1997
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Physical Description: |
129 p. |
Document Type: |
Report Book |
Research Program: |
ohne Topic |
Series Title: |
Berichte des Forschungszentrums Jülich
3455 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
The magnetic properties of Mn overlayers in the submonolayer range on the ferromagnetic substrates Fe(100) and Ni(100) and of fee-Fe overlayers on Cu(100) andCo(100) have been investigated by means of magnetic circular dichroism in x-ray absorption spectroscopy (MCXD). Additionally, spin and angular resolved photoelectronspectroscopy (SARPES) has been applied to study the surface region of the fcc-Fe overlayers. Furthermore magnetic circular dichroism in the soft x-ray emission process (XE-MCD) has been investigated. The net magnetic moment of submonolayer quantities of Mn is found to couple antiparallel to the Fe moment and parallel to the Ni moment. The sign of the magnetic coupling depends on the chemical environment of the Mn atoms. On Fe(100) Mn coverages between 1/50 ML and 1 ML have been investigated. For a coverage of 1/50 ML Mn the spectral shape of the Mn dichroism signal agrees well with the result of an atomic calculation from Ref. [52] on a Mn$^{2+}$ ion in 3d$^{5}$ configuration, indicating that Mn is in a high-spin state. At a Mn coverage of 1/50 ML the MCXD asymmetries of Mn and Fe are of equal size which means that a large fraction of the Mn overlayer is ferromagnetically ordered. Due to the tendency of Mn to antiferromagnetism the net Mn moment decreases rapidly with increasing Mn coverage. For the complete monolayer the net Mn moment reaches zero. This finding confirms recent theoretical predictions [8, 7, 58] of ferrimagnetism within the Mn monolayer where both magnetic sublattices were found to have magnetic moments which are comparable in size but of opposite sign.On the second ferromagnetic substrate the temperature dependence of the magnetization M(T) of the c(2x2) NiMn/Ni(100) surface alloy has been studied. This couldbe done without heating the sample - and therefore preventing it from interdiffusion - because the Ni(100) substrate has been realized by ultrathin Ni overlayers onCu(100) in order to reduce the Curie temperature of Ni from the bulk value (627 K) to values at or below room temperature. By use of MCXD the critical temperaturesT$_{c}$ and the empirical critical exponents $\beta$ of M(T) have been determined for Mn and Ni. As expected for this ferromagnetically coupled surface alloy system, the critical temperatures of Mn and Ni are found to be identical. The Mn atoms are located [...] |