Proceedings a/the DAE Solid State Physics Symposium (2004) Abstract Electronic Transport across Swift Heavy Ion Irradiated Magnetic -Metal / Si Interface P. C. Srivastava J K Tripathi and P.S.Pandey Department of Physics, Banaras Hindu University,Varanasi-221005 Electronictransport across swift heavy ion irradiated (l00 MeV, Fe7+ions,id4cm-2)Fe/Si and Fe20NisriSinterfaces. been studied. The electronic transport has also been studied under low magneticfield of -500 Gauss. it has bee1i,/ol that the irradiated devices show a significant increased current and significant influence of the magnetic field after irradiation. The unirradiated devices do not show the effect of magneticfield. The observed results seems to be due to irradiationinduced intermixed semiconducting magnetic interfacial layer. INTRODUCTION I Magnetic metaUsemiconductor interfaces have gained significance in recent years due to the possibility of spin polarised injection through such interfaces.. Moreover, giant magnetoresistance (GMR) in magnetic multilayersZ has attracted great interest due to their potential for important technical applications such as disk drive read heads.The study of electronic transport through such interfaces has become significant because of the above features. The interface controls significantly the electronic flow through such interfaces and hence the interface modification has a significant role, e.g., GMR is closely related to the scattering of conduction electrons at or near the interfaces in the antiferromagnetic phase. Among the various techniques available, ion beam irradiation has been proved to be a very effective tool because of the two advantages. First, it is able to modify the interface structure of a single existing multilayer systematically am~ controllably. Second, the ballistic nature of ion-beam mixing at low temperature makes it possible to completely mix two elements even in an immiscible system with positive mixing heat. In view of the above features, we have taken up the present study to irradiate FelSi and FezoNisolSi devices by swift (- 100 MeV) heavy ions of Fe7+ . The bilayer devices have been characterized by I-V characteristics before, after the irradiation and in low magnetic fields (up to 500G ). It has been found that the current across the interface has increased by an order of magnitude after the irradiation and shows a str~ng effect under low magnetic field, applied along the plane of the bilayer device. Unirradiated devices do not show the effectofmagneticfield. . , "i1 I ! , i i I I I i I I 'II I !~ I l i EXPERIMENTAL pSi <100> wafers of 8-10 Qcm has been used for the fabrication of FelSi and FezoNisolpSidevices by electron beam evaporation technique. The above fabricated 1.5x10~ 1.Oxt04 (a) ~Befontlm:latkrl -A-AAer ImIdaICft .1.Ox104 .t.5x104 -1.5 .a.s -1.0 0.0 0.5 1.0 -e-Bcininldialia -,-,.irA181i:8 i 0.0 -4.Ox10" -1.5 0.5 1.0 .1.0 .a.s C~).O v-"» Figs.l(a) and (b) : I-V (::haracteristics of Fe/Si and:, FezoNisolSi Devices before and after the 100 MeV: (Fe7l of 10.4 cm'z Irradiation devices were irradiated by 100MeV Fe7+ions for a dose of. ° -10.4 cm-z at Nuclear Science Centre, New Delhi from the 15 UD pelletron facility. Electrical characterizations of the above devices have been done from I-V technique before irradiation, after 506