Kev tshawb pom los ntawm cov hlau nplaum thiab cov kev sim laser tuaj yeem ua rau muaj txiaj ntsig zoo rau cov ntaub ntawv txuag hluav taws xob.
"Peb xav kawm lub physics ntawm optomagnetic kev sib cuam tshuam," said Rahul Jangid, uas coj cov ntaub ntawv tsom xam rau qhov project thaum nws khwv tau nws Ph.D. hauv cov ntaub ntawv tshawb fawb thiab engineering raws li kev coj ntawm Roopali Kukreja, tus kws tshaj lij ntawm UC Davis. "Dab tsi tshwm sim thaum koj ntaus lub sib nqus sib nqus nrog lub laser mem tes luv luv?"
Ib tug sau yog ib cheeb tsam nyob rau hauv ib tug hlau nplaum uas tig los ntawm tus ncej qaum teb mus rau sab qab teb ncej. Cov cuab yeej no yog siv rau cov ntaub ntawv khaws cia, xws li hauv computer hard disk drives.
Jangid thiab nws cov npoj yaig pom tias thaum lub hlau nplaum raug ntaus los ntawm lub tshuab laser, cov phab ntsa hauv cov txheej txheem ferromagnetic txav ntawm li 66 kilometers ib ob, uas yog kwv yees li 100 lub sij hawm sai dua li yav tas los xav ceev txwv.
Domain phab ntsa txav ntawm qhov nrawm tuaj yeem cuam tshuam li cas cov ntaub ntawv khaws cia thiab ua tiav, muab nrawm dua, ruaj khov nco thiab txo lub zog siv ntawm spintronics, xws li hard disk drives, uas siv electron spin nyob rau hauv ntau txheej ntawm hlau nplaum los khaws cia, txheej txheem lossis xa cov ntaub ntawv.
Jangid tau hais tias "Tsis muaj leej twg xav tias cov phab ntsa no tuaj yeem txav nrawm nrawm vim tias lawv yuav tsum ncav cuag lawv qhov txwv," Jangid tau hais. "Nws suab kiag li txiv tsawb, tab sis nws muaj tseeb." Nws yog "bananas" vim yog qhov tshwm sim ntawm Walker tawg, uas hais tias cov phab ntsa tuaj yeem tsuas yog thawb kom deb li deb ntawm qhov muab ceev ua ntej lawv ua haujlwm zoo thiab tsis txav mus. Txawm li cas los xij, txoj kev tshawb no muab pov thawj tias lasers tuaj yeem siv los tsav cov phab ntsa ntawm qhov tsis paub dhau los.
Thaum feem ntau cov khoom siv ntawm tus kheej xws li laptops thiab xov tooj ntawm tes siv flash drives sai dua, cov chaw zov me nyuam siv pheej yig dua, qeeb zog dua. Txawm li cas los xij, txhua zaus cov ntaub ntawv me ntsis ua tiav lossis hloov pauv, cov tsav tsheb hlawv ntau lub zog los ntawm kev siv cov hlau nplaum los ua cov cua sov los ntawm cov coils. Yog tias cov tsav tsheb tuaj yeem siv laser pulses ntawm cov txheej sib nqus, cov khoom siv yuav ua haujlwm ntawm qhov qis dua thiab lub zog xav tau rau me ntsis flipping yuav txo qis heev.
Cov kev kwv yees tam sim no qhia tias ICTs yuav suav txog 21 feem pua ntawm lub ntiaj teb kev xav tau lub zog los ntawm 2030, ua rau muaj kev hloov pauv huab cua, qhov kev tshawb pom tseem ceeb los ntawm Jangid thiab cov kws sau ntawv hauv ib daim ntawv hu ua "Extreme Domain Wall Velocities under Ultrafast Optical Excitation," uas tau luam tawm. Kaum Ob Hlis 19 hauv phau ntawv Journal Physical Review Letters. Qhov kev tshawb pom los ntawm lub sijhawm thaum kev tshawb nrhiav cov thev naus laus zis txuag hluav taws xob tseem ceeb heev.
Txhawm rau ua qhov kev sim, Jangid thiab nws cov neeg koom tes, suav nrog cov kws tshawb fawb los ntawm National Institute of Science thiab Technology; University of California, San Diego; Lub Tsev Kawm Ntawv Qib Siab Colorado, University of Colorado Springs, thiab Stockholm University tau siv Lub Chaw Tshawb Fawb Txog Kev Tshawb Fawb Txog Kev Tshawb Fawb Txog Kev Tshawb Fawb Txog Kev Siv Hluav Taws Xob Dawb Dawb, lub tshuab hluav taws xob dawb dawb nyob hauv Trieste, Ltalis.
"Lub Free Electron Laser yog qhov chaw vwm," Jangid tau hais. "Nws yog 2- mais ntev lub tshuab nqus tsev vacuum qhov twg koj nqa ib tug puv tes ntawm electrons, ceev lawv mus rau qhov ceev ntawm lub teeb, thiab thaum kawg viav vias lawv ib ncig los tsim X-rays ci li ntawd yog hais tias koj tsis ceev faj, koj Piv txwv li yuav vaporized, xav tias nws yog tsom mus rau tag nrho cov hnub ci uas ntog rau lub ntiaj teb ntawm ib lub nyiaj npib-uas yog ntau npaum li cas photon flux peb muaj nyob rau ntawm lub free-electron laser.
Ntawm Fermi, pab pawg siv X-rays los ntsuas qhov tshwm sim thaum cov hlau nplaum nanoscale nrog ntau txheej ntawm cobalt, hlau, thiab npib tsib xee zoo siab los ntawm femtosecond pulses. Ib qho femtosecond txhais tau tias yog 10 rau qhov rho tawm kaum tsib ntawm ib thib ob, lossis ib lab ntawm ib billionth ntawm ib thib ob.
Jangid tau hais tias "Muaj ntau femtoseconds hauv ib thib ob dua li muaj hnub nyob rau hauv lub hnub nyoog ntawm lub ntiaj teb," Jangid tau hais. "Cov no yog me me, ntsuas nrawm heev, thiab nws nyuaj rau koj lub taub hau ncig lawv."
Jangid tab tom tshuaj xyuas cov ntaub ntawv thiab tau pom tias nws yog cov laser pulses ultrafast uas excite lub ferromagnetic txheej, ua rau cov phab ntsa domain txav. Raws li qhov ceev ceev cov phab ntsa no txav mus, txoj kev tshawb fawb qhia tias cov laser pulses ultrafast tuaj yeem hloov cov ntaub ntawv khaws tseg txog 1,000 zaug sai dua li cov hlau nplaum sib nqus lossis tig-tam sim no raws li txoj kev siv niaj hnub no.
Cov txheej txheem yog deb ntawm cov tswv yim vim hais tias tam sim no lasers siv ntau lub zog. Txawm li cas los xij, Jangid hais tias cov txheej txheem zoo ib yam li cov uas siv los ntawm cov disks compact los khaws cov ntaub ntawv siv lasers thiab CD players los ua cov ntaub ntawv siv lasers tuaj yeem ua haujlwm yav tom ntej.
Cov kauj ruam tom ntej no suav nrog kev tshawb fawb ntxiv txog lub cev lub cev ntawm lub tshuab uas tso cai rau cov phab ntsa ultrafast domain ceev tshaj qhov kev txwv yav dhau los paub, nrog rau kev ntsuas lub suab ntawm phab ntsa. Qhov kev tshawb fawb no yuav txuas ntxiv ntawm UC Davis nyob rau hauv Kukreja tus thawj coj.Jangid tam sim no ua kev tshawb fawb zoo sib xws ntawm National Synchrotron Light Source 2 ntawm Brookhaven National Laboratory.
Jangid tau hais tias "Muaj ntau yam ntawm cov xwm txheej ceev ceev uas peb nyuam qhuav pib nkag siab," Jangid tau hais. "Kuv mob siab los daws qee cov lus nug zoo uas tuaj yeem qhib qhov kev hloov pauv hloov pauv hauv thaj chaw qis zog spintronics, cov ntaub ntawv khaws cia thiab cov ntaub ntawv ua haujlwm."
