Hyperfinc Interactions 61 (1990) 1051-1066
1051
NMR A N D NQR OF Cu IN HT c S U P E R C O N D U C T O R S Hans
LUTGEMEIER
Institut f Festk6rperforschung, Kernforschungsanlage Jiilich Gmblt, P.O. Box 1913, D-5170 Jiilich, FRG
After a review of recent results concerning the electric fichl gradient, Knight shift and s p i n - l a t t i c e rehtxation mainly in the 123 supcrcomhlctors, the antiferromagnetic structure of this system and tile influcHce of l"e-impuritics are discussed. In the last part first results for the Bi based superconductors are presented. l.
IN'I'IK) t)tJCTION
A common feature of all the known high T,: super(ot~tluctit,g materials, up to now, is tim existence of the c u e 7 pl:tnes. Tim electronic aml mag,letic start'. ~lf tile Cu ions betweell :hi M ;tnd :|d In in tlle:;c pla,cs i:; i;(,llcr;dly :tssuulcd IJ* I~. I.l~q' Iwy fiJr im(h'r:;L;tmlilq- the mech;tillS, Ill r:,f Slll)cfctmductivity in Lh~).';r c~mil)~mmls. ,~illC(' I.h(' (Jil nuclei plt~l)c tlwir surrtHlndings via their magnetic dipole moments, #, and their electric qua(lrlq)ole moments, cQ, nuclear resonance, either NQI( or NMIt , is best suited for investigating tile state of f,'u. Most Cu resonance experiments have been performed in the system I{l':l~a.~Cua()v where the signals from the Cu sites itt the CH(').~ plaues, Cur2), itntl in the cur) c],;tiJlcS, (hi(I), can be distinguished /I,72/. In this system, the transition from a sul)crecmductor with T(:=92 K to an antiferromag~let with 'l'~:,tt.)0 K m~ the remowd of oxygen frmn y--7 Lt) y=fl l(:ads to a strong static hyperfine field at t{,e C,,(2) sites /:~,,I/ whe,eas the Cl,(l) sites remain nonmagnetic. In tile (l~aSr)TCuO4 system the Cu resonance I,~s been observed il, the ;t,,tiferromagnetic /5,6/ as well as in the superconducting state /6,7,8/..qi,nilar e• have I)een performed in the Ill based S,Jl)t'.rctmductors , ;kS well /9,10,11/. This contribution contains four l)arts: after a short introduction into Cu NQR attd NMIt tile results for superconducting YI]a;!Cu3Oy will I)c rc'.vicwed. Tim tiurd part concerns the magnetic structure of the antifcrromagnetic state f()~ {;.{lerflne field. A third componenL with A|';cl ().5 m m / s r(,v(,Ms no ttt;tl:ttt'tic splitLHq" down to 4.2 1{ a~d musL be :tscr+bed t~r I,'e on latLice tit?feeLs. WithotJt I"u dolling, ;t.n il~h()illo(~,.:lt(!()tl.'c; tt;tnsiti,)tt al I,)w teltll)t:r;ttllre was [Olll~d only [or three samples, (m(: (+f which c(mt;Um'd Nd i~stu;u{ l Lhc I"e i()ns in (-HIT fllOCJO]. /\(;COF(]ilI~ t(~ our CXI)CIieIIEC, howe+v(!]-, LJlc LI;tIIsILIoII tS .'ml)l~r(:ssed by excess of oxygen: For (I.'2% I"e a cleai transiLion is found aL y::~(.$.t) ])ill 11() Li;lll.',fiLit)ll aL y:=(J.[3. T h u s ,.,re condH(]e LhaL n(~t the+ oxyg, eu is the read;on feJr the transition huL~'-;~m~c, magl~eLic i m p u r i t i e s at the Cu($) sites in Lhe sinl'le crystals used in the u(.'uLr(m s(:aLte~inl,' Cxl{erim(mLs
IL Liilgemeiet; N M R and N Q R o f Ctt in l i t c superconductors
1059
The two structnres are different with respect t . till, relaxation tiehaviour as well / 4 0 / I"or the pure nndol)ed sample with tim +o--t o-- stJucturc ;tt y:~().l.~ the transverse relaxation time, 'l'2, seen from the Sl}inq?cho decay is temperature del~vmh'nt and reveals a lniililrliiln at If~ K without any change hi tile line position or width A similar t e . l p c r a t u r e delmndenceis found also by M a t s u m u r a et al. in the NQIi line aiul i. the high fiequency antiferromagnetic lille at 91 Mllz /46/. ]llcre,'t.b a soCi)li(] i)]l;lSc wil+h lower '1',. is t!vidc'iiL \%'(' h;tvt~ iiwcstigaLed the NMI{ .~pcct.r;l at fixr frequency ;uld the NQI{ spectra of ;ll)l~ui+ t(tii .~;++ilil)h's frt)m diffcrciil, tl,igili ;tt ,12 I< ;Ind r.und that they ~Lrc ;all very similar / I 1/. lit're we show ()lily tlic spectra of Llios(! Lwo Sililiplcs or tlic 2212 ;uld 222~l phases with 'l',:=t-17 K ;llid I ILl K, resl~ccLively , which rcveM the bcsl. ph:u~(' puril.v ill LI,('. X--r,'l.y invostigaLI(.HI+ The tr;l.usitioll ciIrvc th.'+tcrillincd [r()lll Lilt d.(:.-';llS(:('lJtil)iliLy II"il;.lt)), however, provos LhiiL the 222:1 sltUll)lo+c, COll[;lill 3. I,'/.rg~c ,'l.lllOtlil[ o[ ul;i.teri;ll wiLh h)wcr "1',:. This s:Unl)lo has boca I)rClJarod [rom a sLarLing lnaLcii~l in which 153/0 o[ Llic Ill wore roplacod by Pb. 'J'ho field-sweep spectra (Fig. 11) were LlLko+ii ;LL 50 M l l z fur fiJl(~ ix~wder sanil)les which could be partly oriented in Lhe lli;lglleLic field (l>re[ercnti~LI oricntaLiotl wiLli Lilt c--it• perpendicular to Lll(~ f i e l d ) Iflith .~l)Cl:Lrit re.vc;~l Lilt: (ill IC.c,OII;LIICC ()r I,oi.h IS, iLlll)C,4 wiLll qu;t(lruliole +splittint; hy aii I']F{I widely disLiilJuLod ~Lrolinll ;l. ,~ingle v,%lllc coriosl)()iltliiig I+() 1],/ 27 M l l z for fL1Cii 3.rid 7/=0 No oLhcr qu;idrut)oh: rrequencieic.I)m, ,%lid Slate C.,..b fi.I (Ib~7) 2(;7 II. l,iitgemeieJ, Physic,t C153--155 (1988) 95. ll. Liitgemcier, M.W. Pieper, \.V. [Ioeh,(:r, U I(,tdcr, J Ilau,:k, 1( ["ischer, F. Zucht, 13. R.UplJ and I!;. [!;bert, Physica CI53--155 (1988) 7;~1 11. 'fasuoka, T. Shiulizu and Y Ueda,.I Phvs St)(:..I;tl)al~ 57 (1988)"" . .d,53t Y. Yamada, K. Ishida, Y. Kitaoka, K Asayaiu;t, 1] Takagi, 11. lwabuchi and S. Uchida, .I. l'hys. Soc..lapan 57 (1988) 2663 T. Tsu(la, T. Shimizu, 11. Ya.suoka, K. Kisliic~aNd K Kit;iz;tw;t,.I. Phys. Soc..}al)an 57
(1988) ~o(,8. /6/ /7/ /8/ /9/ /10/ /11/ /12/ /13/ /I,1/
/15/ /16/ /17/ /18/ /19/ /20/ /21/ /21a /22/'
K. I(ulnagai and Y. Nakamura, I'hysic;t CI57 (198!)) :;(17. K. Ishida, Y. Kitaokaand K. As,'tyama,.]. I'hys Soc .]al)an,,,~R (1989)3d. *1'. lmai, T. Shimizu, 11. Yasuoka, Y. Uc'da, 1,2. Yoshimura and K. l(osuge, [SSP Tech. Repofl. No. 21,15 (1989). 1I. Yasuoka, T [mai and T. ,'ghiinizu, l.qSl' Tcch. lr No. 2168 (1989) T. Oashi, K. Kumagai, Y. Naka.iiiu;t , '1' 'l',,mita a,d T I",].lita, I'hysic,t (].l,r,7 (1989) 315. K. I,'ujiwara, Y. Kitaoka, 1(. Asayama, [1. S;tsakui;t, .'-; MiNaliligawa, 1(. N;,kahigashi, S. N;tkanishi, M. Kogachi, N. I"ukuoka and A Yan;tsc, .I Phys Sot:..l:q)an 58 (1989) 380. IL Michalak, M. Rosenberg and II. lAitge.mt'icr, l'mc M211TSC Stanford (I989), to be published in Physica (3. T.P. Das and I'].L I[;din, Solid State I'h.ysil:s Suppl I, (edited by I" Seitz and D Turnbull (Academic Press, New York, 19.58). l{..l",. Walstedt, W . W Warre.n, .Ir., It.l,'. Bell, (;I,' I;runm'rt, ( ; P gspinosa, It.l. (,itv;t, I,.l". S(:hneemeyer and .I.V. Waszczak, ['hys. l{cv 11;18(1988)9299. A.J. Vega, WI,L I'~;trneth, I';M McCarron and It K llordia, I'hys ltev 1/39 (1989) 2;{22. C.I[. Iq!nningtoii, I).,I. ])llrand, I) 11 Z:lx, f" 1' .~licht,!l, .] [' I{J((~ ;tlld ILM (;iilsl)erg, Phys. I{.c.v ll37 (1988)79,1d "i'. Kohori, 11. Shib;d, Y. Oda., Y. I I,ctt. ,18 (1988)18{i, the value Ihysi
