Portal de Periódicos da CAPES

An intensity standard for electron paramagnetic resonance using chromium-doped corundum (Al2O3: Cr3+)

1978; The National Institute of Standards and Technology; Volume: 83; Issue: 2 Linguagem: Inglês

10.6028/jres.083.008

2376-5259

Tieyan Chang, Donald Foster, Arnold H. Kahn,

Magneto-Optical Properties and Applications

We re port on the pre paration of a sta ndard re fe re nce ma te ri a l (S RM) , mad e of s ing le-crystal c hromium-doped corundum (synth e ti c ruby), for use as a n in te ns it y s tandard in e lectron param agne ti c reso nan ce (EPR) ex pe rim e nt s .Th e S B.M ca n be used to measure, b y compari son, th e number of SI)ins in an unknown tes t sa mpl e.We se lecte d the above mat e ria l for the s tanda rd because its magne tic resona nce prope rti es are we ll understood and because it is phys ica ll y and c he mi ca ll y stab le und e r common laboratory condit ion s.To pre pa re sa mpl es whi c h ga ve sa ti s factory EPR s igna ls, it was necess ary to perform annea lin g and chemi ca l etchin g afler cUllin g.This removed strain s and surface damage.Aft er trea tm ent, th e C,':3+ resonance lin es we re sharper and th e int ensiti es we re in good ag reeme nt with the theore ti ca ll y predi c ted va lues.To a id in app lica ti on, th e theore ti ca l resona nce fi e ld s a nd li n e int e ns iti es we re ca lc ul ated and tabulated for arbi trary ori entation s ortlle sa mpl e, at se vera l com monl y used mi crowave frequ encies .Th e concentrat ion of C,"+ in the sa mpl es was de te rmin ed by measure me nt of th e sta ti c suscep ti bilit y.A quantitative EPR int ensit y ex perim ent , ba sed on measurin g th e mi crowav e power absorbed during reso nance, gave th e sa me conce nt ra tion .This proves, th at within ex perim enta l errol' th e EPR ex pe rime nt de tec ts a ll th e C ,~+ ion s in the sa mpl e, whi c h mak es the ru by a usefu l S RM.