Aqueous suspensions of p
ar
am
agnetic l
anth
anide oxide n
anop
articles h
ave been studied by NMR rel
axometry.The observed
![](/isubscribe/journ<font color=)
als/jpccck/111/i28/eqn/jp072288le10001.gif"> rel
axivities
are expl
ained by the st
atic deph
asing regime (SDR) theory. The corresponding
R2 rel
axivities
are consider
ably sm
aller
and
are strongly dependent on the interv
al between the two refocusingpulses. The experiment
al d
at
a are r
ation
alized by
assuming the v
alue of the diffusion correl
ation time,
![](/im<font color=)
ages/gifch
ars/t
au.gif" BORDER=0 >
D, tobe very long in
a l
ayer with
adsorbed x
anth
an on the p
article's surf
ace. In this l
ayer, the refocusing pulses
are fully effective
and
R2 ![](/im<font color=)
ages/entities/
ap.gif"> 0. Outside this l
ayer, the diffusion model for we
akly m
agnetized p
articles w
as
applied. From the fit of the experiment
al rel
ax
ation d
at
a with this model, both the p
article r
adii (
rp)
and ther
adii of the spheres, within which the refocusing pulses
are fully effective (
rdiff), were estim
ated. The v
aluesof
rp obt
ained
are in
agreement with those determined by dyn
amic light sc
attering. Bec
ause the v
alue of
rdiffdepends on the extern
al m
agnetic field
B and on the m
agnetic moment of the l
anth
anide of interest (
![](/im<font color=)
ages/entities/mgr.gif">
eff2), the
R2 rel
axivity w
as found to be proportion
al to
B and to
![](/im<font color=)
ages/entities/mgr.gif">
eff2.