S.Mochizukietal./PhysicaB308–310(2001)1046–10491047

sinteredat1273Kinairfor24h.FirsttypesofEu2O3 lmsweregrownonasilicaglasssubstratebytheradio-frequencysputtering(RFS)method.TheyarenamedRFS lms.Second-typeofEu2O3 lmsweregrownonasilicaglasssubstratebythepulsedlaserablation(PLA)methodinvacuumof1.33Â10À4Pa.TheyarenamedPLA- lms.Eu2O3microcrystal-accumulated lmsweregrownonasilicaglasssubstratebythePLAmethodinoxygengasofthepressurelowerthan100Pa.TheyarenamedPLA-MC lm.TheyarecharacterizedbytheX-raydi raction(XRD)methodandthescanningelectronmicroscopy(SEM).IrradiationswerecarriedoutwithaCWHe–Cdlaserline(l¼325nm)withpowerdensitiesbetween31438and840000W/m2.ThesameHe–Cdlaserlineexcitesluminescence.Emittedlightisdispersedanddetectedusingagratingspectrographequippedwithamultichannelphotodetectionsystem.

Eu2O3-RFS lm,Eu2O3-PLA lmandEu2O3-PLA-MC lm,respectively.Inthemeasurementsofthepowdercompact,theRFS lms,thePLA lmsandthePLA-MC lms,theirrelativesensitivitiesofthedetec-tionsare1,8,170and34,respectively.Experimentswerecarriedoutinalphabeticalorder:(a)-(b)-(c).Irradia-tiontimetirunderagivenatmosphereandthekind

of

3.Resultsanddiscussion

TheXRDanalysisoftheproducedspecimensindicatesthatthepowdercompact,RFS lm,PLA lm,andPLA-MC lmarerespectively,theCphase,theHphase[1],amixtureofpredominantlyCphasewithalittleBphase,andamixtureofpredominantlyBphasewithalittleCphaseofEu2O3.ThespecimenswerealsoexaminedbytheSEM.Thepowdercompactsconsistofrandomlyorientedandconnectedrectangular-parallele-pipedgrains,asshowninFig.1(a).TheRFS- lmsandthePLAoneshavesmoothsurfacesandareopticallytransparent.ThePLA-MC lmsconsistofalotofsmallparticleswhosesizesisapproximatelyseveralhundrednanometersandlittleaggregateswhosesizescanbeseveralthousandnanometers,asshowninFig.1(b).Figs.2–5showthephotoinducedspectralchangesatroomtemperatureoftheEu2O3-powdercompact,

Fig.2.ReversiblespectralchangeofEu2O3powder

compact.

Fig.3.ReversiblespectralchangeofEu2O3 lmproducebytheRF-sputteringmethod.

Fig.1.SEMphotographsoftheEu2O3-powdercompact(a)andEu2O3-PLA-microcrystal lm

(b).