Temperature, magnetic field and laser excitation power dependence of the photoluminescence (PL) was studied in 5x[EuS(5.5 nm)-PbS(17.5 nm)] semiconductor ferromagnetic multilayer grown epitaxially by high vacuum deposition on BaF2 (111) substrate. In EuS-PbS heterostructures ferromagnetic layers of EuS form electron barriers for both electrons and holes in nonmagnetic quantum wells of PbS. The PL was observed in the near infrared due to electronic transitions in PbS quantum wells with narrow energy gap. The measurements carried out at T=4.2 and 77 K (i.e. below and above the Curie temperature of EuS layers equal about 14 K) showed the characteristic PL spectra consisting of one or two lines with strongly nonlinear response upon increasing the YAG laser excitation power. Below the Curie temperature, the application of a weak magnetic field of 200 Oe results in a change of the PL intensity as well as a small red shift of about 1 meV of the PL energy. These observations are discussed in terms of a model taking into account the magnetization dependent height of EuS potential barrier for electrons in PbS quantum well.
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