Universidad Nacional Autónoma de México - CNyN

1st International Symposium on Nanoscience and Nanomaterials
ORAL SESSION
O-001
PHOTOLUMINECENCE OF EUROPIUM-ACTIVATED HYDROXYAPATITE NANOPARTICLES
IN BODY FLUIDS
M. J. Oviedo 1,a , O. Contreras 2 , R. Vazquez-Duhalt 3 , G.G. Carbajal Arizaga 4 , G.A. Hirata 2,b and J. McKittrick 5
1 Programa de Posgrado en Física de Materiales, CICESE-UNAM. Carretera Ensenada-Tijuana No. 3918, CP
22800. Ensenada, Baja California, México.
2 Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 carretera
Ensenada-Tijuana, CP 22800. Ensenada, Baja California, México.
3 Instituto de Biotecnología, UNAM, Av. Universidad 2001, CP 62250. Cuernava, Morelos, México.
4 Departamento de Química. Universidad de Guadalajara. Marcelino García Barragán 1421, CP 44430.
Guadalajara, Jalisco, México.
5 University of California at San Diego, Mechanical and Aerospace Engineering and Materials Science and
Engineering Program, La Jolla, CA 92093-0411
a moviedo@cnyn.unam.mx, bhirata@cnyn.unam.mx
Keywords: Hydroxyapatite, phosphor, body fluid, biomarker.
Hydroxyapatite (Ca10(PO4)6(OH)2, HA) nanoparticles activated with Eu3+ were synthesized using
the sol–gel technique. The crystal structure was elucidated by X-ray diffraction analysis and the internal
crystal structure and morphology was studied by transmission electron microscopy. Under excitation with 394
nm light, the powders are red-emitting. The photoluminescence bands are detected at 575 nm (5D07F0),
~590 nm (5D07F1), 613 nm (5D07F2) and 626 nm (5D07F2). The nanosized HA:Eu dispersed in
urine and blood serum showed high stability with respect to their optical properties, although some transitions
underwent a change in relative emission intensities. A change in emission intensities was also observed for
the cysteine dispersion. The stability at different pHs was studied in water and urine fluids. The HA:Eu
nanoparticles are suitable as biomarkers for medical applications.
O-002
ENHANCEMENT OF THE PIEZO AND FERROELECTRIC RESPONSE OF MULTIFERROIC
YCrO 3 FILMS BY REDUCTION IN THICKNESS
M. P. Cruz 1,a , D. Valdespino 2 , M. Herrera 1 , J. Muñoz 3 , A. C. García 4 , A. Durán 1 , J.M. Siqueiros 1 , M. Curiel 1
and R. Castañeda 5
1 Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM),
Km. 107, Carretera Tijuana-Ensenada, Ensenada, B.C., México, C.P. 22860.
2 Posgrado en Ciencia e Ingeniería de Materiales, CNyN-UNAM.
3 Centro de Investigación y de Estudios Avanzados (CINVESTAV), Libramiento Norponiente No. 2000,
Fraccionamiento Real de Juriquilla, C.P. 76230, Qro, México.
4 Maestría en Ciencias, CINVESTAV, Qro.
5 Centro de Ciencias Aplicadas y Desarrollo Tecnológico, UNAM, Cd. Universitaria, Circuito Exterior S/N,
C.P. 14510, México D.F.
a mcruz@cnyn.unam.mx
Keywords: multiferroic, magnetoelectric, ferroelectric, piezoelectric, thin films.
The influence of thickness on the piezoelectric response and polarization switching of YCrO3 films,
deposited on Pt/TiO 2 /Si by PLD at room temperature and then annealed at 900ºC/1hr, is presented in this
10