caa a22 4500 463217608 CHVBK 20180405153202.0 cr unu---uuuuu 170326e20070701xx s 000 0 eng 10.1007/s00269-007-0147-9 doi (NATIONALLICENCE)springer-10.1007/s00269-007-0147-9 Low temperature magnetism and Mössbauer spectroscopy study from natural goethite [Elektronische Daten] [T. Berquó, R. Imbernon, A. Blot, D. Franco, M. Toledo, C. Partiti] In this work a magnetic characterization was made of natural goethite from Burkina Faso, Africa, by using low temperature magnetization curves, hysteresis loops, Mössbauer spectroscopy at room temperature and 4.2K, and AC susceptibility from 10 to 400K. The samples are from two distinct geological sites that underwent different weathering processes. All measurements point to the occurrence of typical high coercivity goethite. Through Mössbauer spectroscopy sample BL44, from Gangaol, northeast Burkina Faso showed relaxation effects due to a wide distribution of grain size, including superparamagnetism threshold. AC susceptibility also supports this interpretation. The sample BL50 from Bonga in Burkina Faso is associated with lateritic Ni and in addition to goethite this sample also contained magnetite, as determined by Verwey transition in low temperature measurements as well as a small content of hematite identified by Mössbauer spectroscopy. Springer-Verlag, 2007 Goethite nationallicence Gossans nationallicence Magnetization nationallicence AC susceptibility nationallicence Mössbauer spectroscopy nationallicence Berquó T. Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil aut Imbernon R. Laboratório de Hidrogeoquímica, Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil aut Blot A. IRD—Orstom, 01 BP 182, Ouagadougou, Burkina Faso aut Franco D. Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil aut Toledo M. Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil aut Partiti C. Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil aut Physics and Chemistry of Minerals Springer-Verlag 34/5(2007-07-01), 287-294 0342-1791 34:5<287 2007 34 269 https://doi.org/10.1007/s00269-007-0147-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00269-007-0147-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Berquó T. Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Imbernon R. Laboratório de Hidrogeoquímica, Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Blot A. IRD—Orstom, 01 BP 182, Ouagadougou, Burkina Faso aut NATIONALLICENCE 700 1- Franco D. Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Toledo M. Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Partiti C. Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brazil aut NATIONALLICENCE 773 0- Physics and Chemistry of Minerals Springer-Verlag 34/5(2007-07-01), 287-294 0342-1791 34:5<287 2007 34 269 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer