I nhau c6 cau hinh AP Di/di tac dung cua iii tnidng ngoai, cau hinh AP se chuyen thinh cau hinh P Khi d6, iH do cua tat c^ cac dp deu song song vdi iil tri/dng
56 Nguyin Huu Diic
NM/FM/NM/IS/NM/FM/NM bay gid se trd thanh: NFNINFN. Dudi day, mot sd
cau true lai da va dang dxiac nghien c(iu nhieu d tren the gidi se dUdc gidi thi^ụ
FIF: Day la ki^u cau hinh TMR đn gian dau ti^n ma Julliere da de xuat:
Idp each dign I (Ge) dxiac kep giufa hai kim loai dien ci/c F khac nhau (Fe va Co). Cau hinh T M R cd b i n nay da dxiac nghien ei/u kha thau dao v^ e i ly thuyet Ian
tht/c nghignị
FNIF: Viec them mot Idp NM ciing vdi Idp each dien lam Idp dem chung cho hai
dien eUc FM cho phep tang ca ti sd MR va dp cam iii - dien trd (MR/H).
FIFIF: La cau true TMR cd bin kep, cho phep tang cUdng ti sd TMR; bang each
thay đi th^' hieu dich cd the thay đi dau cua ti sd TMR.
FIFilFglF: dxicfc ehd đi la se cho ti sd TGM ki luc (2000%) nhd vi^c thi^'t l^p
dUdc hai gieng lUdng tif phu thupc spin ben trong F, va F2.
NFIFN: Vdi viec them vao Idp NM d cac dien cUe, ti sd MR se phu thupc vao chieu day Idp FM. Ti sd MR cd dang dao dong theo dp day ciia Idp FM va
cd th^ nhan dxiac gia tri kha quan d cac dieu kien tdi Uụ Cac ed che vat ly cua hi^n tUdng nay cdn mdi, can dxiac nghien cifụ
FINIF: Harig rao kep d\J(?c kep bdi mdt Idp khdng ti/ tinh NM, sau do hang rao
kep hieu dung nay mdi bi kep bdi hai dien cUe FM. Day la cau true lai mdị Cac k^'t q u i nghien cifu budc dau cho thay rang trong cau true nay ti sd MR cung cd dang dao dong khi thay đi kich thude Idp NM. Gia tri MR cao ed the nhan dUdc neu suf dung cac dien eifc ed dp phan cUc spin cao va
chpn dxiac chieu day Idp NM tdi Uụ
Cac h& TMR vi/a neu la cac vi du dien hinh v^ yg'u td va khi nang "nhan
tao" trong viec thiet lap cac he vat lieu va linh kien cd cau true nanọ Bang each đ, chung ta cd the dieu khien cau hinh vat lieu de the nghiem cac y tudng vat ly mdị Vay nen, đi vdi cac he TMR cd cau triic nhan tao nhU vay, cdn cd rat nhieu
cac hien tUdng vat ly mdi dang chd đi d phia trUdc. no cd the xuat hien ngay
ngay mai, trong thang tdi hoac vao cac nam tiép theo tuy thuoc vao ed gang dau
Spintronics dUa tren hieu Ung tit- dien tr6.., 57