{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,17]],"date-time":"2025-09-17T14:50:18Z","timestamp":1758120618221,"version":"3.32.0"},"reference-count":0,"publisher":"International Union of Crystallography (IUCr)","issue":"4","license":[{"start":{"date-parts":[[2003,7,19]],"date-time":"2003-07-19T00:00:00Z","timestamp":1058572800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/journals.iucr.org\/services\/copyrightpolicy.html"},{"start":{"date-parts":[[2003,7,19]],"date-time":"2003-07-19T00:00:00Z","timestamp":1058572800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/journals.iucr.org\/services\/copyrightpolicy.html#TDM"}],"content-domain":{"domain":["iucr.org","wiley.com","iucrj.org"],"crossmark-restriction":true},"short-container-title":["J Appl Crystallogr","J Appl Cryst"],"published-print":{"date-parts":[[2003,8,1]]},"abstract":"Hybrid organic\u2013inorganic nanocomposites doped with FeII<\/jats:sup>and FeIII<\/jats:sup>ions and exhibiting interesting magnetic properties have been obtained by the sol\u2013gel process. The hybrid matrix of these ormosils (organically modified silicates), classed as di-ureasils and termed U(2000), is composed of poly(oxyethylene) chains of variable length grafted to siloxane groups by means of urea crosslinkages. Iron perchlorate and iron nitrate were incorporated in the di-ureasil matrices, leading to compositions within the range 80 \u2265n<\/jats:italic>\u2265 10,n<\/jats:italic>being the molar ratio of ether-type O atoms per cation. The structure of the doped di-ureasils was investigated by small-angle X-ray scattering (SAXS). For FeII<\/jats:sup>-doped samples, SAXS results suggest the existence of a two-level hierarchical structure. The primary level is composed of spatially correlated siloxane clusters embedded in the polymeric matrix and the secondary, coarser level consists of domains where the siloxane clusters are segregated. The structure of FeIII<\/jats:sup>-doped hybrids is different, revealing the existence of iron oxide based nanoclusters, identified as ferrihydrite by wide-angle X-ray diffraction, dispersed in the hybrid matrix. The magnetic susceptibility of these materials was determined by zero-field-cooling and field-cooling procedures as functions of both temperature and field. The different magnetic features between FeII<\/jats:sup>- and FeIII<\/jats:sup>-doped samples are consistent with the structural differences revealed by SAXS. While FeII<\/jats:sup>-doped composites exhibit a paramagnetic Curie-type behaviour, hybrids containing FeIII<\/jats:sup>ions show thermal and field irreversibilities.<\/jats:p>","DOI":"10.1107\/s0021889803008410","type":"journal-article","created":{"date-parts":[[2003,7,22]],"date-time":"2003-07-22T18:04:10Z","timestamp":1058897050000},"page":"961-966","update-policy":"https:\/\/doi.org\/10.1107\/cm_01","source":"Crossref","is-referenced-by-count":8,"title":["Structure of magnetic poly(oxyethylene)\u2013siloxane nanohybrids doped with FeII<\/sup>and FeIII<\/sup>"],"prefix":"10.1107","volume":"36","author":[{"given":"N. J. O.","family":"Silva","sequence":"first","affiliation":[]},{"given":"K.","family":"Dahmouche","sequence":"additional","affiliation":[]},{"given":"C. V.","family":"Santilli","sequence":"additional","affiliation":[]},{"given":"V. S.","family":"Amaral","sequence":"additional","affiliation":[]},{"given":"L. D.","family":"Carlos","sequence":"additional","affiliation":[]},{"given":"V. de Zea","family":"Bermudez","sequence":"additional","affiliation":[]},{"given":"A. F.","family":"Craievich","sequence":"additional","affiliation":[]}],"member":"329","published-online":{"date-parts":[[2003,7,19]]},"container-title":["Journal of Applied Crystallography"],"original-title":[],"link":[{"URL":"http:\/\/journals.iucr.org\/j\/issues\/2003\/04\/00\/ks7327\/ks7327.pdf","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/journals.iucr.org\/j\/issues\/2003\/04\/00\/ks7327\/ks7327.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,1,11]],"date-time":"2025-01-11T14:01:41Z","timestamp":1736604101000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.iucr.org\/paper?S0021889803008410"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2003,7,19]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2003,8]]}},"alternative-id":["S0021889803008410"],"URL":"https:\/\/doi.org\/10.1107\/s0021889803008410","relation":{},"ISSN":["0021-8898"],"issn-type":[{"type":"print","value":"0021-8898"}],"subject":[],"published":{"date-parts":[[2003,7,19]]},"assertion":[{"value":"Journal of Applied Crystallography","name":"journal","label":"Journal","explanation":{"URL":"http:\/\/journals.iucr.org\/j"}},{"value":"research papers","name":"content_type","label":"Content type","explanation":{"URL":"http:\/\/journals.iucr.org\/j\/services\/notesforauthors.html"}},{"value":"Yes","order":0,"name":"peer_reviewed","label":"Peer reviewed","group":{"name":"peer_review","label":"Peer review"}},{"value":"Single blind","order":1,"name":"review_process","label":"Review process","group":{"name":"peer_review","label":"Peer review"}},{"value":"29 August 2002","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication history"}},{"value":"14 April 2003","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication history"}},{"value":"19 July 2003","order":2,"name":"published_online","label":"Published online","group":{"name":"publication_history","label":"Publication history"}},{"value":"\u00a9 2003 International Union of Crystallography","order":0,"name":"copyright","label":"Copyright","explanation":{"URL":"http:\/\/journals.iucr.org\/services\/copyrightpolicy.html"},"group":{"name":"copyright_and_licensing","label":"Copyright and licencing"}}]}}